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HCV-related lymphoproliferative disorders in the direct-acting antiviral era: From mixed cryoglobulinaemia to B-cell lymphoma

  • Patrice Cacoub
    Correspondence
    Corresponding author. Address: Department of Internal Medicine and Clinical Immunology, Hôpital La Pitié-Salpêtrière, 47-83, boulevard de l’Hôpital, 75651 Cedex 13. Paris. France. Tel.: + 33 (0) 1 42 17 80 27; fax: + 33 (0) 1 42 17 80 33.
    Affiliations
    AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Department of Internal Medicine and Clinical Immunology, Paris, France

    Centre de Référence des Maladies Auto-Immunes Systémiques Rares, Centre de Référence des Maladies Auto-Inflammatoires et de l’Amylose inflammatoire, F-75013, Paris, France

    Institut National de la Santé et de la Recherche Médicale, INSERM, UMR_S 959, F-75013, Paris, France

    CNRS, FRE3632, F-75005, Paris, France

    Sorbonne Université, UPMC Univ Paris 06, Inflammation-Immunopathology-Biotherapy Department (DHU i2B), F-75005, Paris, France
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  • Cloé Comarmond
    Affiliations
    AP-HP, Lariboisière Hospital, Department of Internal Medicine and Clinical Immunology, Paris, France
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  • Matheus Vieira
    Affiliations
    AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Department of Internal Medicine and Clinical Immunology, Paris, France

    Centre de Référence des Maladies Auto-Immunes Systémiques Rares, Centre de Référence des Maladies Auto-Inflammatoires et de l’Amylose inflammatoire, F-75013, Paris, France

    Institut National de la Santé et de la Recherche Médicale, INSERM, UMR_S 959, F-75013, Paris, France

    CNRS, FRE3632, F-75005, Paris, France

    Sorbonne Université, UPMC Univ Paris 06, Inflammation-Immunopathology-Biotherapy Department (DHU i2B), F-75005, Paris, France
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  • Paul Régnier
    Affiliations
    AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Department of Internal Medicine and Clinical Immunology, Paris, France

    Centre de Référence des Maladies Auto-Immunes Systémiques Rares, Centre de Référence des Maladies Auto-Inflammatoires et de l’Amylose inflammatoire, F-75013, Paris, France

    Institut National de la Santé et de la Recherche Médicale, INSERM, UMR_S 959, F-75013, Paris, France

    CNRS, FRE3632, F-75005, Paris, France

    Sorbonne Université, UPMC Univ Paris 06, Inflammation-Immunopathology-Biotherapy Department (DHU i2B), F-75005, Paris, France
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  • David Saadoun
    Affiliations
    AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Department of Internal Medicine and Clinical Immunology, Paris, France

    Centre de Référence des Maladies Auto-Immunes Systémiques Rares, Centre de Référence des Maladies Auto-Inflammatoires et de l’Amylose inflammatoire, F-75013, Paris, France

    Institut National de la Santé et de la Recherche Médicale, INSERM, UMR_S 959, F-75013, Paris, France

    CNRS, FRE3632, F-75005, Paris, France

    Sorbonne Université, UPMC Univ Paris 06, Inflammation-Immunopathology-Biotherapy Department (DHU i2B), F-75005, Paris, France
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Published:September 29, 2021DOI:https://doi.org/10.1016/j.jhep.2021.09.023

      Summary

      HCV has been shown to induce many B-cell lymphoproliferative disorders. B lymphocytes specialise in producing immunoglobulins and, during chronic HCV infection, they can cause manifestations ranging from polyclonal hypergammaglobulinaemia without clinical repercussions, through mixed cryoglobulinaemic vasculitis to B-cell non-Hodgkin lymphoma. This spectrum is supported by substantial epidemiological, pathophysiological and therapeutic data. Many, although not all, of the pathogenic pathways leading from one extreme to another have been decrypted. Chronic viral antigen stimulation of B lymphocytes has a central role until the final steps before overt malignancy. This has direct implications for treatment strategies, which always include the use of direct-acting antivirals sometimes alongside immunosuppressants. The role of direct-acting antivirals has been well established in patients with cryoglobulinaemia vasculitis. However, their positive impact on B-cell non-Hodgkin lymphoma needs to be confirmed in larger studies with longer follow-up.

      Keywords

      Introduction

      HCV is estimated to infect more than 70 million people worldwide. Although hepatotropic in essence, chronic HCV infection has been associated with many extrahepatic manifestations, which have been observed in up to two-thirds of patients.
      • Cacoub P.
      • Poynard T.
      • Ghillani P.
      • Charlotte F.
      • Olivi M.
      • Charles Piette J.
      • et al.
      Extrahepatic manifestations of chronic hepatitis C.
      Cryoglobulinaemia – characterised by the presence of circulating cryoglobulins – is the most frequent extrahepatic manifestation and is present in half of patients. Cryoglobulins are the product of chronically stimulated B lymphocytes and can be seen as hypergammaglobulinaemia on serum protein electrophoresis.
      Lymphoproliferative disorders, either benign such as cryoglobulinaemia vasculitis, or malignant such as B-cell non-Hodgkin lymphoma (B-NHL), represent well-described extrahepatic manifestations of HCV and appear to represent both ends of the spectrum of systemic virus-induced disease.
      • Cacoub P.
      • Saadoun D.
      Extrahepatic manifestations of chronic HCV infection.
      Lymphocytes share the same CD81 transmembrane receptor as hepatocytes; the viral envelope protein E2 binds to this receptor and leads to several changes in lymphocyte homeostasis. A complex multistep process supports the progression from asymptomatic cryoglobulinaemia to cryoglobulinaemic vasculitis (CryoVas) and ultimately to overt B-cell malignancy.
      • Roccatello D.
      • Saadoun D.
      • Ramos-Casals M.
      • Tzioufas A.G.
      • Fervenza F.C.
      • Cacoub P.
      • et al.
      Cryoglobulinaemia.
      The fact that cryoglobulinaemia is the main risk factor for the development of B-NHL reinforces the link between these entities.
      • Monti G.
      • Pioltelli P.
      • Saccardo F.
      • Campanini M.
      • Candela M.
      • Cavallero G.
      • et al.
      Incidence and characteristics of non-hodgkin lymphomas in a multicenter case file of patients with hepatitis C virus–related symptomatic mixed cryoglobulinemias.
      Several other mechanisms and arguments have since endorsed this. The sustained virological response (SVR) following interferon-alpha (IFN-α)-based therapeutic regimens has been proven to reduce the risk of developing both CryoVas and B-NHL in HCV-infected patients.
      • Mahale P.
      • Engels E.A.
      • Li R.
      • Torres H.A.
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      • Brown E.L.
      • et al.
      The effect of sustained virological response on the risk of extrahepatic manifestations of hepatitis C virus infection.
      With the recent advent of direct-acting antivirals (DAAs), which are well-tolerated therapies that lead to higher rates of SVR, great enthusiasm has been generated around their potential beneficial effects on extrahepatic manifestations. The purpose of this review is to describe the updated basis for our existing perspective on the lymphoproliferation continuum — from cryoglobulinaemia to B-NHL — within chronic HCV infection, with a focus on the impact of DAAs on these conditions. The reader is referred to other recent and comprehensive reviews covering aspects of HCV extrahepatic manifestations with distinct perspectives.
      • Cacoub P.
      • Saadoun D.
      Extrahepatic manifestations of chronic HCV infection.
      ,
      • Roccatello D.
      • Saadoun D.
      • Ramos-Casals M.
      • Tzioufas A.G.
      • Fervenza F.C.
      • Cacoub P.
      • et al.
      Cryoglobulinaemia.
      ,
      • Couronné L.
      • Bachy E.
      • Roulland S.
      • Nadel B.
      • Davi F.
      • Armand M.
      • et al.
      From hepatitis C virus infection to B-cell lymphoma.

      Epidemiology and clinical manifestations

      HCV-related mixed cryoglobulinaemia vasculitis

      Epidemiology

      Mixed CryoVas is a small-vessel systemic vasculitis. Before the era of DAAs, HCV was the main cause of mixed cryoglobulinaemia, accounting for between 70% and 90% of cases, depending on geographic region. Available since 2014, DAA regimens provided a highly effective antiviral treatment for HCV, which modified this picture. Currently, systemic autoimmune disorders (mainly systemic lupus erythematosus and Sjögren's syndrome) and haematological malignancies appear to be the main causes of mixed cryoglobulinaemia in developed countries, with HCV infection ranking third, as noted in a recent study we conducted in France.
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      • Musset L.
      • Biard L.
      • Mulier G.
      • Cacoub P.
      • et al.
      Cryoglobulinemia after the era of chronic hepatitis C infection.

      Main clinical features

      HCV was the main cause of cryoglobulinaemic vasculitis prior to the DAA era, and now systemic autoimmune disorders and haematological malignancies appear predominant.
      Mixed cryoglobulinemia vasculitis may lead to clinical manifestations ranging from purpura, arthralgia and fatigue to more serious and life-threatening complications with neurologic and renal involvement (Fig. 1).
      • Cacoub P.
      • Renou C.
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      • et al.
      Extrahepatic manifestations associated with hepatitis C virus infection. A prospective multicenter study of 321 patients. The GERMIVIC. Groupe d’Etude et de Recherche en Medecine Interne et Maladies Infectieuses sur le Virus de l’Hepatite C.
      The main cutaneous manifestation is palpable purpura. Raynaud’s phenomenon, acrocyanosis, skin ulcers and chronic ulcerations of the lower limbs can also occur. Joint involvement commonly appears as non-erosive arthralgia that affects large joints, whereas arthritis is rare. The most frequent neurological manifestation is distal sensory or sensory-motor polyneuropathy. Multiple mononeuropathy may occur less frequently. Regarding renal involvement, alterations on urinalysis are frequently seen, although they often occur without clinical repercussion. The more frequent and severe clinically relevant renal manifestation is membranoproliferative glomerulonephritis. Acute renal failure and nephritis syndrome may be the first manifestations of renal involvement. Renal biopsy shows type I membranoproliferative glomerulonephritis in more than 70% of patients. Less frequent renal histopathologic patterns include mesangio-proliferative or membranous glomerulopathy. Other associated histopathological lesions include the presence of crescents, necrotising vasculitis, interstitial inflammation and capillary luminal cryoglobulin thrombi. Immunofluorescence studies demonstrate IgG, IgM, and C3 within most of the cryoglobulin deposits present in the capillary loops; C1q is seen in about one-third of patients. Histological features of the nerve and kidney in CryoVas are shown in Fig. 2.
      Figure thumbnail gr1
      Fig. 1Main HCV-cryoglobulinaemic vasculitis manifestations.
      The target organs of cryoglobulinaemic vasculitis are illustrated together with the respective frequencies with which they occur. Basic epidemiological aspects are shown in the upper left corner. CNS, central nervous system; NHL, non-Hodgkins lymphoma.
      Figure thumbnail gr2
      Fig. 2HCV-cryoglobulinaemic vasculitis pathology.
      (A) Peripheral nerve biopsy showing a large perivascular infiltrate of Th1 lymphocytes located around small vessels (i.e., venules, capillaries); of note is the absence of polymorphonuclear cells or destruction of the vascular wall. (B) Kidney biopsy showing membranoproliferative glomerulonephritis using optical microscopy (left) and electron microscopy (right). Th1, type 1 T helper.

      HCV-related lymphomas

      Epidemiology

      An association between HCV infection and B-NHL has been reported since the virus was first identified, and observations from several studies have been confirmed in meta-analyses. Gisbert et al.
      • Gisbert J.P.
      • García-Buey L.
      • Pajares J.M.
      • Moreno-Otero R.
      Prevalence of hepatitis C virus infection in B-cell non-Hodgkin’s lymphoma: systematic review and meta-analysis.
      pooled data from 5,542 patients and estimated the prevalence of HCV infection to be 15% among patients with B-NHL, which is considerably higher than that observed in the general population (1.5%) and in patients with other haematologic malignancies (2.9%). Another meta-analysis comprising 15 case-control and 3 prospective studies yielded a relative risk (RR) for B-cell NHL among patients with HCV of 2.5 (95% CI 2.1–3.0). A striking geographic variation in B-NHL prevalence was noted, as the RR in countries with high HCV prevalence (≥5%) was 3.01, while in those with low prevalence it was 1.9. Overall, it has been estimated that HCV could account for up to 10% of B-NHL cases in countries with high HCV prevalence, but less than 1% in low-prevalence countries.
      Another argument for the role of HCV in lymphomagenesis came from early reports and case series that associated SVR achievement to lymphoma regression, as well as the recurrence of positive viraemia to lymphoma relapse.
      • Casato M.
      • Mecucci C.
      • Agnello V.
      • Fiorilli M.
      • Knight G.B.
      • Matteucci C.
      • et al.
      Regression of lymphoproliferative disorder after treatment for hepatitis C virus infection in a patient with partial trisomy 3, Bcl-2 overexpression, and type II cryoglobulinemia.
      ,
      • Saadoun D.
      • Suarez F.
      • Lefrere F.
      • Valensi F.
      • Mariette X.
      • Aouba A.
      • et al.
      Splenic lymphoma with villous lymphocytes, associated with type II cryoglobulinemia and HCV infection: a new entity?.
      If HCV is considered at the origin of B-NHL, viral eradication should have a favourable impact on lymphoma development over time. Early positive results derived from a large cohort of patients with HCV treated with IFN-based therapies demonstrated a reduction in B-NHL incidence in those who reached SVR (hazard ratio [HR] 0.13).
      • Kawamura Y.
      • Ikeda K.
      • Arase Y.
      • Yatsuji H.
      • Sezaki H.
      • Hosaka T.
      • et al.
      Viral elimination reduces incidence of malignant lymphoma in patients with hepatitis C.
      The annual incidence of B-NHL among patients with HCV was estimated as 0.23%. The main limitation of such results is related to the well-known immunomodulatory properties of IFN, which may have induced B-NHL regression regardless of its antiviral effect. This trend has been further confirmed in recent large retrospective studies. A nationwide Taiwanese real-world cohort evaluated 10,714 patients who had received IFN-based therapy and were followed over a median of 3.79 years.
      • Huang C.-F.
      • Lai H.-C.
      • Chen C.-Y.
      • Tseng K.-C.
      • Kuo H.-T.
      • Hung C.-H.
      • et al.
      Extrahepatic malignancy among patients with chronic hepatitis C after antiviral therapy: a real-world nationwide study on Taiwanese chronic hepatitis C cohort (T-COACH).
      Patients not reaching an SVR had a significantly higher risk of developing B-NHL than those with an SVR (0.08% vs. 0.03% per person-year, respectively; p = 0.03). Notably, this effect was seen only in patients younger than 65 years, reinforcing the prospect that early antiviral treatment should be the rule. In an even larger cohort of 69,581 American veterans (predominantly males) with HCV, an IFN-induced SVR was able to significantly reduce the B-NHL incidence over a mean follow-up period of 10.6 years (adjusted HR [aHR] 0.70; 95% CI 0.51–0.97).
      • Dal Maso L.
      • Franceschi S.
      Hepatitis C virus and risk of lymphoma and other lymphoid neoplasms: a meta-analysis of epidemiologic studies.
      Interestingly, a reduction in the combined incidence of all B-cell haematologic malignancies (including multiple myeloma) and monoclonal gammopathy of undetermined significance was also noted (aHR 0.67; 95% CI 0.53–0.84). Although a DAA-induced SVR was not shown to have the same benefit in this study, it is still not possible to draw definite conclusions, as follow-up data are available for a much shorter period in DAA-treated compared to IFN-treated patients (2.9 vs. 10.6 years, respectively).
      Different types of B-cell lymphomas have been associated with HCV, the mostly low-grade ones occurring in the spleen or liver.

      B-cell lymphoma subtypes

      Different types of B-NHL have been associated with HCV infection. An early meta-analysis found a consistently higher risk for all B-NHL subtypes.
      • Dal Maso L.
      • Franceschi S.
      Hepatitis C virus and risk of lymphoma and other lymphoid neoplasms: a meta-analysis of epidemiologic studies.
      However, the strongest associations were with low-grade B-NHLs occurring in the spleen or liver, namely marginal zone lymphoma (MZL) and lymphoplasmacytic lymphoma, and with high-grade diffuse large B-cell lymphoma (DLBCL). A large international case-control study reported odds ratios of 2.47 (95% CI 1.44–4.23), 2.57 (95% CI 1.14–5.79) and 2.24 (95% CI 1.68–2.99) for these 3 subtypes, respectively.
      • Sanjose S de
      • Benavente Y.
      • Vajdic C.M.
      • Engels E.A.
      • Morton L.M.
      • Bracci P.M.
      • et al.
      Hepatitis C and non-Hodgkin lymphoma among 4784 cases and 6269 controls from the International Lymphoma Epidemiology Consortium.
      Other low-grade B-NHLs, such as follicular lymphoma (FL) and chronic lymphocytic leukaemia, were not associated with HCV. A large American case-control study confirmed the association between MZL and DLBCL.
      • Anderson L.A.
      • Pfeiffer R.
      • Warren J.L.
      • Landgren O.
      • Gadalla S.
      • Berndt S.I.
      • et al.
      Hematopoietic malignancies associated with viral and alcoholic hepatitis.
      HCV-associated DLBCL can occur de novo or as a result of MZL transformation. A multicentric study demonstrated that DLBCL in HCV-positive patients most frequently arose from transformed MZL when compared with those without HCV (32% vs. 6%, p = 0.02), endorsing the continuum that exists in HCV-induced lymphoproliferation.
      • Paulli M.
      • Arcaini L.
      • Lucioni M.
      • Boveri E.
      • Capello D.
      • Passamonti F.
      • et al.
      Subcutaneous “lipoma-like” B-cell lymphoma associated with HCV infection: a new presentation of primary extranodal marginal zone B-cell lymphoma of MALT.
      Some peculiar B-NHL subtypes have been specifically associated with HCV in case series, such as splenic MZL with villous lymphocytes
      • Saadoun D.
      • Suarez F.
      • Lefrere F.
      • Valensi F.
      • Mariette X.
      • Aouba A.
      • et al.
      Splenic lymphoma with villous lymphocytes, associated with type II cryoglobulinemia and HCV infection: a new entity?.
      and subcutaneous ‘lipoma-like’ extranodal MZL,
      • Paulli M.
      • Arcaini L.
      • Lucioni M.
      • Boveri E.
      • Capello D.
      • Passamonti F.
      • et al.
      Subcutaneous “lipoma-like” B-cell lymphoma associated with HCV infection: a new presentation of primary extranodal marginal zone B-cell lymphoma of MALT.
      which is apparently responsive to antivirals. A monoclonal gammopathy, mainly IgMk, has also been reported in HCV-infected patients.
      • Andreone P.
      • Zignego A.L.
      • Cursaro C.
      • Gramenzi A.
      • Gherlinzoni F.
      • Fiorino S.
      • et al.
      Prevalence of monoclonal gammopathies in patients with hepatitis C virus infection.
      A large US Veterans Affairs study found that HCV promoted a 3-fold higher risk of Waldenström macroglobulinaemia, which was not found for multiple myeloma.
      • Giordano T.P.
      • Henderson L.
      • Landgren O.
      • Chiao E.Y.
      • Kramer J.R.
      • El-Serag H.
      • et al.
      Risk of non-Hodgkin lymphoma and lymphoproliferative precursor diseases in US veterans with hepatitis C virus.

      Clinical presentations

      There are several features that make the lymphoma presentation peculiar among patients with HCV. First, the age of onset seems to be lower in HCV-infected patients, as B-cell NHL was reported to be diagnosed on average 4.6 years earlier than in those without the virus.
      • Allison R.D.
      • Tong X.
      • Moorman A.C.
      • Ly K.N.
      • Rupp L.
      • Xu F.
      • et al.
      Increased incidence of cancer and cancer-related mortality among persons with chronic hepatitis C infection, 2006-2010.
      Among patients with HCV, the presence of CryoVas is by far the strongest risk factor for developing B-NHL, with affected patients having a 35 times greater risk than the general population.
      • Monti G.
      • Pioltelli P.
      • Saccardo F.
      • Campanini M.
      • Candela M.
      • Cavallero G.
      • et al.
      Incidence and characteristics of non-hodgkin lymphomas in a multicenter case file of patients with hepatitis C virus–related symptomatic mixed cryoglobulinemias.
      Other reported risk factors include female gender, long-lasting infection and being from an HCV endemic region.
      • Ferri C.
      • Feld J.J.
      • Bondin M.
      • Cacoub P.
      Expert opinion on managing chronic HCV in patients with non-Hodgkin lymphoma and other extrahepatic malignancies.
      As for the clinical presentation, splenomegaly or extranodal involvement (i.e. liver, salivary glands) have been reported more often in HCV-positive than HCV-negative patients.
      • De Vita S.
      • Sacco C.
      • Sansonno D.
      • Gloghini A.
      • Dammacco F.
      • Crovatto M.
      • et al.
      Characterization of overt B-cell lymphomas in patients with hepatitis C virus infection.
      Infected patients were also shown to have more frequent monoclonal gammopathy and cryoglobulinaemia (probable consequences of long-lasting B-cell activation). All these characteristics were recently reproduced in a large prospective multicentre cohort, and highlighted that autoimmune phenomena are more common among indolent compared to aggressive lymphomas.
      • Rattotti S.
      • Ferretti V.V.
      • Rusconi C.
      • Rossi A.
      • Fogazzi S.
      • Baldini L.
      • et al.
      Lymphomas associated with chronic hepatitis C virus infection: a prospective multicenter cohort study from the Rete Ematologica Lombarda (REL) clinical network.
      This distinct clinical presentation also reflects a worse prognosis and a more challenging treatment landscape. A large American cohort study reported higher mortality rates for HCV-infected patients with B-NHL, while death occurred on average 12.6 years earlier than for those without HCV infection.
      • Allison R.D.
      • Tong X.
      • Moorman A.C.
      • Ly K.N.
      • Rupp L.
      • Xu F.
      • et al.
      Increased incidence of cancer and cancer-related mortality among persons with chronic hepatitis C infection, 2006-2010.
      Regarding transformed DLBCL, HCV-infected patients had more relapses and a worse 2-year survival rate than those who were not infected.
      • Hosry J.
      • Miranda R.N.
      • Samaniego F.
      • Economides M.P.
      • Torres H.A.
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      This study also reported that CD5+ B cells — a known marker of poor prognosis — were more frequently seen in HCV-infected than non-infected patients, and their presence was closely associated with B-NHL relapse after chemotherapy. Regarding other treatment modalities, HCV-NHL patients undergoing haematopoietic cell transplantation were reported to progress faster to cirrhosis than those who were not transplanted.
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      • Lévy V.
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      Long-term outcome of hepatitis C infection after bone marrow transplantation.

      Pathophysiology

      Benign lymphoproliferation: cryoglobulinaemic vasculitis

      Cryoglobulinemia is defined as the presence in the serum of an immunoglobulin that precipitates in vitro at 4 °C and dissolves at 37 °C. Circulating mixed cryoglobulins are detected in 40% to 60% of patients who are chronically infected with HCV, while HCV-CryoVas occurs in approximately 15% of HCV-infected patients. Mixed cryoglobulinaemia is characterised by the presence of type II and type III cryoglobulins, which consist of polyclonal IgG with monoclonal and polyclonal IgM, respectively, both with rheumatoid factor (RF) activity. During follow-up, biological improvement is assessed by the serum level of cryoglobulins and surrogate markers (C4 serum level and RF).
      The main risk factors for developing HCV-related lymphoma are the presence of cryoglobulin, female sex, long-lasting infection and being from an HCV endemic region.
      The mechanisms that lead to HCV-induced cryoglobulinaemia and the reasons that cryoglobulinaemia can be symptomatic or asymptomatic are not fully understood. Numerous factors support the autoimmune origin of HCV-related CryoVas, such as the presence of autoantibodies (mixed cryoglobulin with RF activity), the presence of T-cell infiltrates in small-sized vessels, and the observation that specific HLA alleles confer susceptibility to CryoVas.
      • Roccatello D.
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      • Fervenza F.C.
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      Cryoglobulinaemia.
      ,
      • Boleto G.
      • Vieira M.
      • Saadoun D.
      • Cacoub P.
      Hepatitis C virus-related vasculitis.
      The pathophysiological cellular responses guiding this autoimmunity are summarised in Fig. 3. HCV interacts directly with lymphocytes and leads to modulation of B- and T-cell function, which then leads to polyclonal activation and expansion of B cells producing RF.
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      Extrahepatic manifestations of chronic hepatitis C.
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      • Saadoun D.
      • Landau D.A.
      • Calabrese L.H.
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      Hepatitis C-associated mixed cryoglobulinaemia: a crossroad between autoimmunity and lymphoproliferation.
      Abnormal T-cell homeostasis is observed in patients with HCV-CryoVas, with a quantitative defect in regulatory T cells (Tregs) and predominant type 1 T helper cell polarisation.
      • Boyer O.
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      CD4+CD25+ regulatory T-cell deficiency in patients with hepatitis C-mixed cryoglobulinemia vasculitis.
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      • Bon-Durand V.
      • Andreu M.
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      Predominance of type 1 (Th1) cytokine production in the liver of patients with HCV-associated mixed cryoglobulinemia vasculitis.
      The benign B-cell lymphoproliferation likely results from an indirect process following the chronic antigenic stimulation of a limited pool of pre-existing autoreactive B cells. It has been proposed that persistently high levels of HCV-containing immune complexes stimulate the proliferation of RF-bearing B cells, but the precise antigen and stimulatory mechanisms have remained elusive. Clonal expansion of CD27+IgM+CD21low/- memory B cells, referred to as activated or atypical memory B cells (AtMs), has been described in patients with HCV-CryoVas.
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      TLR9 signalling in HCV-associated atypical memory B cells triggers Th1 and rheumatoid factor autoantibody responses.
      AtMs are clonal or clonally related, and mainly express the VH1-69 IgH gene, which is also highly prevalent in HCV-associated malignant lymphoproliferations. Low expression of CD21 on these clonal memory B cells reflects an anergic state.
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      • et al.
      Complement receptor 2/CD21- human naive B cells contain mostly autoreactive unresponsive clones.
      AtMs are prone to undergo apoptosis and do not proliferate upon B-cell receptor (BCR) stimulation, but they respond to the Toll-like receptor 9 agonist CpG by expressing activator and proliferative markers. Anergy is a well-known regulatory mechanism for maintaining immune tolerance of autoreactive cells. AtMs in HCV-CryoVas produce somatically mutated RF autoantibodies and are not removed from the B-cell repertoire. It remains unclear why mechanisms of anergy fail to prevent NHL development in some patients with HCV-CryoVas. Interestingly, in patients with HCV-CryoVas treated with DAAs, the numbers of Tregs increased, IgM+CD21-/low memory B cells decreased, and T follicular helper cells decreased, resolving disturbances in peripheral B- and T-cell homeostasis.
      • Comarmond C.
      • Garrido M.
      • Pol S.
      • Desbois A.-C.
      • Costopoulos M.
      • Le Garff-Tavernier M.
      • et al.
      Direct-acting antiviral therapy restores immune tolerance to patients with hepatitis C virus-induced cryoglobulinemia vasculitis.
      DAA therapy also appears to exert an effect on B-cell phenotype by reducing the proportion of circulating CD21-/low AtMs. Despite this positive impact, B clones may persist in the serum after DAA-induced SVR, but so far, their persistence has not been correlated with reactivation of vasculitis.
      • Visentini M.
      • Del Padre M.
      • Colantuono S.
      • Yang B.
      • Minafò Y.A.
      • Antonini S.
      • et al.
      Long-lasting persistence of large B-cell clones in hepatitis C virus-cured patients with complete response of mixed cryoglobulinaemia vasculitis.
      While the mechanisms behind CryoVas relapses after DAA therapy remain unclear, biomarkers such as monoclonal B-cell lymphocytosis, t(14;18) translocation, and abnormal free light chain κ/λ ratios have been proposed as biological factors that could predict clinical response.
      • Gragnani L.
      • Lorini S.
      • Marri S.
      • Basile U.
      • Santarlasci V.
      • Monti M.
      • et al.
      Hematological and genetic markers in the rational approach to patients with HCV sustained virological response with or without persisting cryoglobulinemic vasculitis.
      Figure thumbnail gr3
      Fig. 3Immune responses leading to autoimmunity during HCV infection (including cryoglobulinaemia vasculitis) and treatment targets.
      Expansion of AtMs is observed in patients with HCV-related cryoglobulinaemia vasculitis. AtMs are clonal or clonally related, and mainly express the VH1-69 IgH gene. These clonal cells have decreased expression of the complement receptor 2, CD21, reflecting an anergic state. However, AtMs respond to TLR9 agonist stimulation by expressing activator and proliferative markers and have a higher expression of T-bet, CD11c, CD80, CD95, and FCRL5 compared with RM B cells in HCV-cryoglobulinaemia vasculitis. TLR signalling on AtMs stimulates the secretion of Th1 cytokines (TNF-α and IFN-γ), promoting proliferation and activation of effector Th1 cells, and conversely reducing Treg proliferation. Stimulated AtMs also secrete IgMs with rheumatoid factor activity in HCV-cryoglobulinaemia vasculitis. Interestingly, the expansion of AtM cells in such patients decreased significantly after DAA treatment. This is likely a consequence of removal of the antigens, and cessation of chronic viral stimulation of autoreactive AtMs following DAA therapy. The main therapeutic molecules of HCV-cryoglobulinaemia vasculitis are represented by red shapes. AtM, atypical memory B-cell; BAFF, B-cell-activating factor; BCR, B-cell receptor; CTLA-4, cytotoxic T lymphocyte antigen-4; DAA, direct-acting antiviral; PE, plasma exchanges; FCRL5, Fc receptor like 5; hi; high; IFN-γ, interferon- γ; Ig, immunoglobulin; IL-2, low-dose interleukin-2; int, intermediate; PD-1, programmed death 1; RF, rheumatoid factor; RM, resting memory; TCR, T-cell receptor; Th1, type 1 T helper cell; TLR, toll-like receptor; TNF-α, tumour necrosis factor-α; Treg, regulatory T cell.

      Malignant lymphoproliferation: lymphoma

      Despite not coding for oncogenes and being unable to be integrated into the host genome,
      • Machida K.
      • Cheng K.T.-N.
      • Sung V.M.-H.
      • Shimodaira S.
      • Lindsay K.L.
      • Levine A.M.
      • et al.
      Hepatitis C virus induces a mutator phenotype: enhanced mutations of immunoglobulin and protooncogenes.
      HCV appears to be involved in lymphomagenesis through diverse non-exclusive mechanisms. As for the lymphotropism seen in CryoVas, the continuous exposure of BCRs to viral antigens plays a major role in malignant clonal expansion, mainly in the MZL subtype, but also in transformed DLBCL.
      • Vannata B.
      • Arcaini L.
      • Zucca E.
      Hepatitis C virus-associated B-cell non-Hodgkin’s lymphomas: what do we know?.
      CD81 engagement with the E2 viral protein has been shown to reduce the B-cell threshold for activation and proliferation, either in isolation
      • Rosa D.
      • Saletti G.
      • De Gregorio E.
      • Zorat F.
      • Comar C.
      • D’Oro U.
      • et al.
      Activation of naïve B lymphocytes via CD81, a pathogenetic mechanism for hepatitis C virus-associated B lymphocyte disorders.
      or in combination with BCR binding along with the CD19/CD21/CD81 complex.
      • Weng W.-K.
      • Levy S.
      Hepatitis C virus (HCV) and lymphomagenesis.
      These interactions are able to directly induce immunoglobulin gene hypermutations, notably in the VH region as described above.
      • Machida K.
      • Cheng K.T.-H.
      • Pavio N.
      • Sung V.M.-H.
      • Lai M.M.C.
      Hepatitis C virus E2-CD81 interaction induces hypermutation of the immunoglobulin gene in B cells.
      The high mutation rate may lead to the production of HCV antibodies with lower affinity and specificity, which favour viral escape from immune surveillance.
      • Machida K.
      • Kondo Y.
      • Huang J.Y.
      • Chen Y.-C.
      • Cheng K.T.-H.
      • Keck Z.
      • et al.
      Hepatitis C virus (HCV)-induced immunoglobulin hypermutation reduces the affinity and neutralizing activities of antibodies against HCV envelope protein.
      E2-CD81 binding could also lead to Bcl-2 rearrangement and t(14;18) translocation — known apoptosis inhibitors — as shown in HCV patients with MALT lymphomas and CryoVas.
      • Libra M.
      • Gloghini A.
      • Malaponte G.
      • Gangemi P.
      • De Re V.
      • Cacopardo B.
      • et al.
      Association of t(14;18) translocation with HCV infection in gastrointestinal MALT lymphomas.
      ,
      • Zignego A.L.
      • Ferri C.
      • Giannelli F.
      • Giannini C.
      • Caini P.
      • Monti M.
      • et al.
      Prevalence of bcl-2 rearrangement in patients with hepatitis C virus-related mixed cryoglobulinemia with or without B-cell lymphomas.
      Besides CD81, the co-stimulatory receptor B7.2 (CD86) mediates lymphotropism through inhibition of memory B-cell function, and thus enhances persistent infection in hosts.
      • Chen C.-L.
      • Huang J.Y.
      • Wang C.-H.
      • Tahara S.M.
      • Zhou L.
      • Kondo Y.
      • et al.
      Hepatitis C virus has a genetically determined lymphotropism through co-receptor B7.2.
      The HCV core protein is also implicated as it was shown to induce B-cell proliferation in patients with HCV-NHL by promoting the production of interleukin-6 by CD14+ cells.
      • Feldmann G.
      • Nischalke H.D.
      • Nattermann J.
      • Banas B.
      • Berg T.
      • Teschendorf C.
      • et al.
      Induction of interleukin-6 by hepatitis C virus core protein in hepatitis C-associated mixed cryoglobulinemia and B-cell non-Hodgkin’s lymphoma.
      B-cell-activating factor (or BAFF), another strong B-cell-stimulating cytokine, has also been associated with HCV-NHL.
      • Sène D.
      • Limal N.
      • Ghillani-Dalbin P.
      • Saadoun D.
      • Piette J.-C.
      • Cacoub P.
      Hepatitis C virus-associated B-cell proliferation--the role of serum B lymphocyte stimulator (BLyS/BAFF).
      These data support the stepwise process involved in HCV-induced lymphoproliferation and reveal additional mechanisms that could be required for the transformation to overt lymphoma.
      Although HCV is capable of infecting lymphocytes, its ability to replicate within these cells in vivo does not appear as vigorous as within hepatocytes.
      • Machida K.
      • Cheng K.T.-N.
      • Sung V.M.-H.
      • Shimodaira S.
      • Lindsay K.L.
      • Levine A.M.
      • et al.
      Hepatitis C virus induces a mutator phenotype: enhanced mutations of immunoglobulin and protooncogenes.
      The so-called “hit and run” theory has been proposed to explain further steps involved in B-cell damage beyond persistent intracellular replication. A mutator phenotype is induced by HCV in vitro, increasing the frequency of mutations in proto-oncogenes and tumour suppressor genes, such as Bcl-6, p53 and beta-catenin. This is further enhanced by the induction of double-strand breaks through activation of error-prone polymerases and activation-induced cytidine deaminase.
      • Machida K.
      • Cheng K.T.-N.
      • Sung V.M.-H.
      • Shimodaira S.
      • Lindsay K.L.
      • Levine A.M.
      • et al.
      Hepatitis C virus induces a mutator phenotype: enhanced mutations of immunoglobulin and protooncogenes.
      Another mechanism relates to nitric oxide production, with oxidative stress causing mitochondrial and DNA damage.
      • Machida K.
      • Cheng K.T.-H.
      • Lai C.-K.
      • Jeng K.-S.
      • Sung V.M.-H.
      • Lai M.M.C.
      Hepatitis C virus triggers mitochondrial permeability transition with production of reactive oxygen species, leading to DNA damage and STAT3 activation.
      Core protein and non-structural protein 3 expression have also been associated with oxidative stress induction.
      • Machida K.
      • Cheng K.T.-H.
      • Sung V.M.-H.
      • Lee K.J.
      • Levine A.M.
      • Lai M.M.C.
      Hepatitis C virus infection activates the immunologic (type II) isoform of nitric oxide synthase and thereby enhances DNA damage and mutations of cellular genes.
      In patients with mixed cryoglobulinaemia, DAAs alongside plasmapheresis and/or rituximab should be given according to the severity of vasculitis.
      The roles of viral particles and intracellular networks have been increasingly emphasised. Non-structural protein 4B has been shown to play a critical role in the activation of Bcl-2 and matrix metalloproteinase-2 through multiple cellular signalling pathways, including several members of the protein kinase C family: JNK, ERK and STAT3.
      • Li Y.
      • Zhang Q.
      • Liu Y.
      • Luo Z.
      • Kang L.
      • Qu J.
      • et al.
      Hepatitis C virus activates Bcl-2 and MMP-2 expression through multiple cellular signaling pathways.
      Of note, the JNK pathway was also reported to be induced by E2-CD81 engagement.
      • Rosa D.
      • Saletti G.
      • De Gregorio E.
      • Zorat F.
      • Comar C.
      • D’Oro U.
      • et al.
      Activation of naïve B lymphocytes via CD81, a pathogenetic mechanism for hepatitis C virus-associated B lymphocyte disorders.
      Non-structural protein 3/4A overexpression ex vivo was recently demonstrated to have a role in the post-transcriptional regulation of target mRNAs, increasing BCR signalling from inside B cells.
      • Dai B.
      • Chen A.Y.
      • Corkum C.P.
      • Peroutka R.J.
      • Landon A.
      • Houng S.
      • et al.
      Hepatitis C virus upregulates B-cell receptor signaling: a novel mechanism for HCV-associated B-cell lymphoproliferative disorders.
      Besides viral particles, the role of microRNAs (miRNAs) in intracellular network regulation has been highlighted. Downregulation of some miRNAs was demonstrated to drive lymphomagenesis in HCV-transgenic mice and activate both canonical and alternative NF-κB pathways.
      • Kasama Y.
      • Mizukami T.
      • Kusunoki H.
      • Peveling-Oberhag J.
      • Nishito Y.
      • Ozawa M.
      • et al.
      B-cell-intrinsic hepatitis C virus expression leads to B-cell-lymphomagenesis and induction of NF-κB signalling.
      The role of miRNA networks is further reinforced by distinct signatures reported in splenic tissue from patients with MZL
      • Peveling-Oberhag J.
      • Crisman G.
      • Schmidt A.
      • Döring C.
      • Lucioni M.
      • Arcaini L.
      • et al.
      Dysregulation of global microRNA expression in splenic marginal zone lymphoma and influence of chronic hepatitis C virus infection.
      ; they have also been found to be potential biomarkers in lymph node samples from DLBCL.
      • Augello C.
      • Gianelli U.
      • Savi F.
      • Moro A.
      • Bonoldi E.
      • Gambacorta M.
      • et al.
      MicroRNA as potential biomarker in HCV-associated diffuse large B-cell lymphoma.
      In turn, the transition between these low- and high-grade subtypes remains poorly understood but has been linked to dysregulation in NOTCH signalling. The frequency of mutations in this pathway, which is known to be involved in MZL pathogenesis, was shown to be much higher in HCV-positive patients with transformed DLBCL than in their HCV-negative counterparts.
      • Arcaini L.
      • Rossi D.
      • Lucioni M.
      • Nicola M.
      • Bruscaggin A.
      • Fiaccadori V.
      • et al.
      The NOTCH pathway is recurrently mutated in diffuse large B-cell lymphoma associated with hepatitis C virus infection.
      There are several mechanisms involved in the HCV lymphoproliferation continuum, regardless of the viral presence within B cells. The processes leading to overt lymphoma are shown in Fig. 4. These are not necessarily mutually exclusive but instead seem to flow in parallel, increasing oncogenic potential. Of note, if HCV is indeed able to cause permanent B-cell damage, a no-return point in lymphoproliferative pathogenesis could limit antiviral efficacy.
      Figure thumbnail gr4
      Fig. 4Pathophysiological processes from benign towards malignant lymphoproliferation during chronic HCV infection.
      The first steps of HCV-related lymphoproliferation are induced by chronic antigen stimulation. E2 protein binds to B cells via a membrane protein complex that includes the CD81 receptor. This binding reduces the B-cell threshold for activation and proliferation, and induces immunoglobulin somatic hypermutation, resulting in hypergammaglobulinaemia. Also, E2-CD81 interaction leads to Bcl-2 rearrangement or t(14;18) translocation, which are known apoptosis inhibitors. After many years of such stimulation, probably associated with other factors (regulatory T-cell deficit, Bcl-2, cytokines), some abnormal immunoglobulins named cryoglobulins are produced: first type III (polyclonal) then type II (polyclonal with monoclonal component) mixed cryoglobulins. In some patients, these cryoglobulins will induce symptomatic cryoglobulinaemia vasculitis. The presence of the monoclonal component in type II cryoglobulinemia demonstrates the underlying B-cell clonal proliferation. While this process remains exclusively dependent on viral stimulation, it can be reversed after achieving sustained clearance of HCV. However, this B-cell clonal expansion may turn out to be antigen-insensitive in some patients, leading to uncontrolled B-cell proliferation, which is the definition of B-cell lymphoma. Indeed, it is postulated that clonal B cells might acquire their own autonomy throughout the lymphoproliferation process. This is at least partially explained by the “hit and run” theory, also supported by several other factors, such as cytokines, mutations in proto-oncogenes and tumour suppressor genes, oxidative stress and finally dysregulation in intracellular networks. Underpinning the lymphoproliferative continuum that exists in chronic HCV infection, cryoglobulinaemic vasculitis is by far the greatest risk factor for lymphomas. High-grade lymphomas (e.g., DLBCL) typically arise from the transformation of low-grade lymphomas (e.g., MZL). However, high-grade lymphomas can also occur as de novo, that is, without necessarily passing through the low-grade lymphoma stage. Follicular subtype appears to follow a distinct course from MZL and de novo DLBCL, which is reviewed in more detail by Couronné et al.
      • Couronné L.
      • Bachy E.
      • Roulland S.
      • Nadel B.
      • Davi F.
      • Armand M.
      • et al.
      From hepatitis C virus infection to B-cell lymphoma.
      AID, activation-induced cytidine deaminase; BAFF, B-cell-activating factor; DLBCL, diffuse large B-cell lymphoma; IL-6, interleukin-6; MZL, marginal zone lymphoma; NO, nitric oxide; PKC, protein kinase C.

      Therapeutic strategies

      HCV-related cryoglobulinaemic vasculitis

      DAAs have drastically changed the treatment of chronic HCV infection.
      European Association for the Study of the LiverClinical practice guidelines panel: chairEASL governing board representative: panel members
      EASL recommendations on treatment of hepatitis C: final update of the series☆.
      DAAs induce SVR rates greater than 95% with very rare and minor side effects. They have also proven efficacious for extrahepatic manifestations such as CryoVas. In the largest prospective study to date, including 148 patients with HCV-CryoVas, a complete clinical response of vasculitis manifestations was observed in 73% of patients (106/148), a partial response in 23% (33/148) and no response in 5% (7/148).
      • Cacoub P.
      • Si Ahmed S.N.
      • Ferfar Y.
      • Pol S.
      • Thabut D.
      • Hezode C.
      • et al.
      Long-term efficacy of interferon-free antiviral treatment regimens in patients with hepatitis C virus-associated cryoglobulinemia vasculitis.
      Cryoglobulinaemia resolved in more than half of patients.
      • Cacoub P.
      • Si Ahmed S.N.
      • Ferfar Y.
      • Pol S.
      • Thabut D.
      • Hezode C.
      • et al.
      Long-term efficacy of interferon-free antiviral treatment regimens in patients with hepatitis C virus-associated cryoglobulinemia vasculitis.
      A complete response was observed for purpura in 97% of patients, renal involvement in 91%, arthralgias in 86% and neuropathy in 77%. The severity of CryoVas and peripheral neuropathy was associated with no or partial response. A therapeutic strategy for HCV-associated renal disease includes DAA combinations, rituximab, plasma exchange, corticosteroids, and rarely cyclophosphamide. The risk of glomerulonephritis appears to be reduced following SVR.
      • El-Serag H.B.
      • Christie I.C.
      • Puenpatom A.
      • Castillo D.
      • Kanwal F.
      • Kramer J.R.
      The effects of sustained virological response to direct-acting anti-viral therapy on the risk of extrahepatic manifestations of hepatitis C infection.
      ,
      • Fabrizi F.
      • Cerutti R.
      • Porata G.
      • Messa P.
      • Ridruejo E.
      Direct-acting antiviral agents for HCV-associated glomerular disease and the current evidence.
      Most HCV-CryoVas manifestations have been shown to resolve after DAA therapy. Across all published DAA studies in patients with symptomatic HCV-CryoVas, long-term follow-up (up to 24 months) has shown high rates of clinical response, either complete (65%) or partial (20%) (Fig. 5). Viral clearance was strongly associated with the resolution of vasculitis manifestations. However, some symptoms of CryoVas seem to be more prone to resolve after SVR while others may remain. On one hand, cutaneous manifestations such as purpura and skin ulcers, articular manifestations and myalgia were most frequently reported to respond rapidly, usually with complete resolution (Fig. 5A). On the other hand, symptoms related to peripheral neuropathy and renal disorders showed a less frequent complete response compared with cutaneous and articular manifestations (30%–70% vs. 75%–100%, respectively).
      • Cacoub P.
      • Si Ahmed S.N.
      • Ferfar Y.
      • Pol S.
      • Thabut D.
      • Hezode C.
      • et al.
      Long-term efficacy of interferon-free antiviral treatment regimens in patients with hepatitis C virus-associated cryoglobulinemia vasculitis.
      ,
      • Sise M.E.
      • Bloom A.K.
      • Wisocky J.
      • Lin M.V.
      • Gustafson J.L.
      • Lundquist A.L.
      • et al.
      Treatment of hepatitis C virus-associated mixed cryoglobulinemia with direct-acting antiviral agents.
      • Gragnani L.
      • Visentini M.
      • Fognani E.
      • Urraro T.
      • De Santis A.
      • Petraccia L.
      • et al.
      Prospective study of guideline-tailored therapy with direct-acting antivirals for hepatitis C virus-associated mixed cryoglobulinemia.
      • Saadoun D.
      • Pol S.
      • Ferfar Y.
      • Alric L.
      • Hezode C.
      • Si Ahmed S.N.
      • et al.
      Efficacy and safety of sofosbuvir plus daclatasvir for treatment of HCV-associated cryoglobulinemia vasculitis.
      • Bonacci M.
      • Lens S.
      • Londoño M.-C.
      • Mariño Z.
      • Cid M.C.
      • Ramos-Casals M.
      • et al.
      Virologic, clinical, and immune response outcomes of patients with hepatitis C virus-associated cryoglobulinemia treated with direct-acting antivirals.
      • Emery J.S.
      • Kuczynski M.
      • La D.
      • Almarzooqi S.
      • Kowgier M.
      • Shah H.
      • et al.
      Efficacy and safety of direct acting antivirals for the treatment of mixed cryoglobulinemia.
      • Passerini M.
      • Schiavini M.
      • Magni C.F.
      • Landonio S.
      • Niero F.
      • Passerini S.
      • et al.
      Are direct-acting antivirals safe and effective in hepatitis C virus-cryoglobulinemia? virological, immunological, and clinical data from a real-life experience.
      • Saadoun D.
      • Thibault V.
      • Si Ahmed S.N.
      • Alric L.
      • Mallet M.
      • Guillaud C.
      • et al.
      Sofosbuvir plus ribavirin for hepatitis C virus-associated cryoglobulinaemia vasculitis: VASCUVALDIC study.
      Figure thumbnail gr5
      Fig. 5Response of HCV-related cryoglobulinaemia vasculitis to DAA therapy.
      Pooled improvement rates with its estimated mean obtained from studies evaluating the response of cryoglobulinaemia vasculitis to HCV-targeting DAA therapy. Clinical response of (A) articular, (B) cutaneous, (C) neurological and (D) renal manifestations of cryoglobulinemia vasculitis, and (E) immunological response (i.e., circulating cryoglobulin clearance) in patients with cryoglobulinemia vasculitis are presented. ∗Total skin manifestations (i.e., both purpura and ulcers). DAA, direct-acting antiviral. Refs. [
      • Cacoub P.
      • Si Ahmed S.N.
      • Ferfar Y.
      • Pol S.
      • Thabut D.
      • Hezode C.
      • et al.
      Long-term efficacy of interferon-free antiviral treatment regimens in patients with hepatitis C virus-associated cryoglobulinemia vasculitis.
      ,
      • Sise M.E.
      • Bloom A.K.
      • Wisocky J.
      • Lin M.V.
      • Gustafson J.L.
      • Lundquist A.L.
      • et al.
      Treatment of hepatitis C virus-associated mixed cryoglobulinemia with direct-acting antiviral agents.
      ,
      • Gragnani L.
      • Visentini M.
      • Fognani E.
      • Urraro T.
      • De Santis A.
      • Petraccia L.
      • et al.
      Prospective study of guideline-tailored therapy with direct-acting antivirals for hepatitis C virus-associated mixed cryoglobulinemia.
      ,
      • Saadoun D.
      • Pol S.
      • Ferfar Y.
      • Alric L.
      • Hezode C.
      • Si Ahmed S.N.
      • et al.
      Efficacy and safety of sofosbuvir plus daclatasvir for treatment of HCV-associated cryoglobulinemia vasculitis.
      ,
      • Bonacci M.
      • Lens S.
      • Londoño M.-C.
      • Mariño Z.
      • Cid M.C.
      • Ramos-Casals M.
      • et al.
      Virologic, clinical, and immune response outcomes of patients with hepatitis C virus-associated cryoglobulinemia treated with direct-acting antivirals.
      ,
      • Emery J.S.
      • Kuczynski M.
      • La D.
      • Almarzooqi S.
      • Kowgier M.
      • Shah H.
      • et al.
      Efficacy and safety of direct acting antivirals for the treatment of mixed cryoglobulinemia.
      ,
      • Passerini M.
      • Schiavini M.
      • Magni C.F.
      • Landonio S.
      • Niero F.
      • Passerini S.
      • et al.
      Are direct-acting antivirals safe and effective in hepatitis C virus-cryoglobulinemia? virological, immunological, and clinical data from a real-life experience.
      ,
      • Saadoun D.
      • Thibault V.
      • Si Ahmed S.N.
      • Alric L.
      • Mallet M.
      • Guillaud C.
      • et al.
      Sofosbuvir plus ribavirin for hepatitis C virus-associated cryoglobulinaemia vasculitis: VASCUVALDIC study.
      ,
      • Bonacci M.
      • Lens S.
      • Mariño Z.
      • Londoño M.-C.
      • Rodriguez-Tajes S.
      • Sánchez-Tapias J.M.
      • et al.
      Long-term outcomes of patients with HCV-associated cryoglobulinemic vasculitis after virologic cure.
      ,
      • Gragnani L.
      • Cerretelli G.
      • Lorini S.
      • Steidl C.
      • Giovannelli A.
      • Monti M.
      • et al.
      Interferon-free therapy in hepatitis C virus mixed cryoglobulinaemia: a prospective, controlled, clinical and quality of life analysis.
      ] are given in the References section.
      Consistent with international guidelines, antiviral therapy should be started without delay in patients with HCV-CryoVas, with an absolute need for the use of DAA therapy to eliminate HCV infection.
      • Saadoun D.
      • Landau D.A.
      • Calabrese L.H.
      • Cacoub P.P.
      Hepatitis C-associated mixed cryoglobulinaemia: a crossroad between autoimmunity and lymphoproliferation.
      ,
      • Boyer O.
      • Saadoun D.
      • Abriol J.
      • Dodille M.
      • Piette J.-C.
      • Cacoub P.
      • et al.
      CD4+CD25+ regulatory T-cell deficiency in patients with hepatitis C-mixed cryoglobulinemia vasculitis.
      A combination of DAAs with plasmapheresis (to clear the cryoglobulins) and/or rituximab (to deplete cryoglobulin-producing B cells) is tailored according to the severity of CryoVas. Patients with mild to moderate CryoVas symptoms (fatigue, arthralgia, purpura, sensory neuropathy) should be treated only with optimised DAA therapy. Severe CryoVas manifestations, such as membranoproliferative glomerulonephritis, skin necrosis, severe neuropathy, gastrointestinal vasculitis, lung involvement, and heart and/or central nervous system vasculitis, require additional immunosuppressive strategies in combination with DAA therapy.
      • Galli M.
      • Monti G.
      • Marson P.
      • Scaini P.
      • Pietrogrande M.
      • Candela M.
      • et al.
      Recommendations for managing the manifestations of severe and life-threatening mixed cryoglobulinemia syndrome.
      The anti-CD20 monoclonal antibody rituximab is the first choice, most frequently administered at a dosage of 375 mg/m2 every week for 4 consecutive weeks, and should always be associated with DAA therapy, although not necessarily at the same time.
      • Ramos-Casals M.
      • Zignego A.L.
      • Ferri C.
      • Brito-Zerón P.
      • Retamozo S.
      • Casato M.
      • et al.
      Evidence-based recommendations on the management of extrahepatic manifestations of chronic hepatitis C virus infection.
      ,
      • Ferri C.
      • Cacoub P.
      • Mazzaro C.
      • Roccatello D.
      • Scaini P.
      • Sebastiani M.
      • et al.
      Treatment with rituximab in patients with mixed cryoglobulinemia syndrome: results of multicenter cohort study and review of the literature.
      ,
      • Zignego A.L.
      • Gragnani L.
      • Visentini M.
      • Casato M.
      Reply.
      Removal of circulating cryoglobulins by therapeutic plasmapheresis is accepted as an adjunctive therapy for fulminant cases or severe exacerbation of vasculitis, especially in those with rapidly progressive glomerulonephritis, central nervous system involvement, cardiac manifestations, ulcers or cutaneous necrotising vasculitis.
      • Desbois A.C.
      • Comarmond C.
      • Saadoun D.
      • Cacoub P.
      Cryoglobulinemia vasculitis: how to handle.
      ,
      • Zignego A.L.
      • Pawlotsky J.-M.
      • Bondin M.
      • Cacoub P.
      Expert opinion on managing chronic HCV in patients with mixed cryoglobulinaemia vasculitis.
      Importantly, during plasmapheresis, the exchange solution should be warmed to body temperature to avoid cryoglobulin precipitation. In case of acute cryoglobulinaemic symptoms, 3 to 8 plasmapheresis procedures should be considered every 1 to 3 days with a 1–1.5 total plasma volume.
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      ,
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      Alternative therapies are limited. Low-dose corticosteroids may help to control inflammatory symptoms such as joint pain. Other conventional immunosuppressants should be given only in case of severe and refractory forms of CryoVas, which are frequently associated with underlying B-NHL.
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      • et al.
      Using rituximab plus fludarabine and cyclophosphamide as a treatment for refractory mixed cryoglobulinemia associated with lymphoma.
      After HCV clearance following DAA therapy in those with only a partial resolution of CryoVas manifestations despite first-line immunosuppressive therapy, the persistence of cryoglobulinaemia or relapse of vasculitis symptoms need to be monitored and alternative therapies assessed (low-dose interleukin 2, belimumab).
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      ,
      • Ostojic P.
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      Patients with B-NHL appear to respond to DAAs, either alone or in combination with chemotherapy, and should be treated with an individualised and multidisciplinary approach that includes close monitoring.
      DAA regimens demonstrate excellent safety and efficacy in patients with HCV-CryoVas. Less than 5% of patients discontinue DAA treatment.
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      Treatment of chronic hepatitis C-associated cryoglobulinemia vasculitis at the era of direct-acting antivirals.
      Of note, the mortality rate associated with HCV-CryoVas is less than 3% in the DAA era compared with 40 to 60% in the IFN era.
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      Treatment of chronic hepatitis C-associated cryoglobulinemia vasculitis at the era of direct-acting antivirals.
      However, achievement of an SVR is necessary but not sufficient to achieve a complete immunological response, as cryoglobulins remain present in about 50% of patients 6 to 12 months following DAA therapy (Fig. 5B). These patients remain at risk of vasculitis relapse and/or of developing B-NHL; as such, long-term follow-up is warranted in this population.

      HCV-related lymphoma

      The different benefits of SVR in NHL have been known since the IFN era. As mentioned above, a large historical cohort showed evidence of a clear reduction in the incidence of B-NHL in patients with an IFN-induced SVR (HR 0.7) but not a DAA-induced SVR (owing to several potential confounders).
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      Eradication of hepatitis C virus is associated with reduction in hematologic malignancies: major differences between interferon and direct-acting antivirals.
      Another large retrospective cohort of American veterans found similar biases when evaluating the potential benefit of DAA therapy on NHL risk.
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      Concerning the impact on B-NHL progression, the proven effect of IFN also seems reproducible with DAAs.
      In international guidelines, HCV treatment is prioritised for those with clinically significant extrahepatic manifestations, including B-NHL.
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      Despite the small sample available for DAA-induced SVR (n = 76 patients), its pooled data yielded an odds ratio of 8.97 (95% CI 2.27–35.37) for reaching PFS. Studies evaluating the responses of B-NHL to DAA treatment are summarised in Fig. 6. Both low- and high-grade B-NHL appear to respond to DAAs, either alone or in combination with chemotherapy, with a 1-year PFS ranging from 75% to 100%. Small lymphocytic lymphoma (also known as chronic lymphocytic leukaemia) seems to be the only exception among B-NHL subtypes.
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      ,
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      To date, the largest cohort evaluated included 66 patients (MZL = 53), with 68% of them responding to isolated DAA therapy.
      • Frigeni M.
      • Besson C.
      • Visco C.
      • Fontaine H.
      • Goldaniga M.
      • Visentini M.
      • et al.
      Interferon-free compared to interferon-based antiviral regimens as first-line therapy for B-cell lymphoproliferative disorders associated with hepatitis C virus infection.
      In patients with low-grade B-NHL, HCV treatment has been recommended as first-line therapy without chemotherapy.
      • Torres H.A.
      • Shigle T.L.
      • Hammoudi N.
      • Link J.T.
      • Samaniego F.
      • Kaseb A.
      • et al.
      The oncologic burden of hepatitis C virus infection: a clinical perspective.
      ,
      • Zignego A.L.
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      • Saadoun D.
      • Arcaini L.
      • Roccatello D.
      • et al.
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      Regarding high-grade B-NHL, a retrospective cohort evaluated DAA combined with chemotherapy in 47 patients and reported a complete haematological response rate of 98% and a 2-year PFS rate of 93.1%.
      • Merli M.
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      • Visco C.
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      • et al.
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      Mild non-hepatic adverse events were reported in 11 (23%) patients, while liver toxicity was experienced by 23 patients (49%), mainly in those receiving DAAs after chemotherapy. In turn, another study that evaluated 20 patients with DLBCL receiving concomitant DAAs and chemotherapy did not observe differences in the adverse event rate when compared with a historical cohort receiving only chemotherapy.
      • Persico M.
      • Aglitti A.
      • Caruso R.
      • De Renzo A.
      • Selleri C.
      • Califano C.
      • et al.
      Efficacy and safety of new direct antiviral agents in hepatitis C virus-infected patients with diffuse large B-cell non-Hodgkin’s lymphoma.
      Although the optimal management of high-grade B-NHL in patients with HCV has yet to be determined, prior administration of DAAs should be able to normalise liver enzymes before chemotherapy, while the concomitant approach achieves this normalisation earlier. Considering potential drug-drug interactions and other clinical particularities, these patients should be treated with an individualised and multidisciplinary approach, involving the close monitoring of both therapies.
      AASLD-IDSA HCV Guidance Panel
      Hepatitis C guidance 2018 update: AASLD-IDSA recommendations for testing, managing, and treating hepatitis C virus infection.
      Figure thumbnail gr6
      Fig. 6Haematological response of B-cell non-Hodgkin lymphoma to direct-acting antiviral therapy.
      Pooled response rates with estimated means obtained from studies evaluating the haematological response of B-cell non-Hodgkin lymphoma to HCV-targeting direct-acting antivirals. (A) Partial and complete responses of low-grade B-cell non-Hodgkin lymphoma. (B) Overall responses of high-grade B-cell non-Hodgkin lymphoma.

      Conclusion

      Three decades after first being detected, HCV has been shown to induce many B-cell lymphoproliferative disorders ranging from hypergammaglobulinaemia and mixed cryoglobulinaemia to MZL and B-NHL. This is supported by substantial epidemiological, pathophysiological and therapeutic evidence. The exact pathogenic pathway that leads from one extreme to another is not fully understood, especially regarding the final steps before overt malignancy. This has direct implications for treatment strategies. While the role of DAAs has been well established in patients with CryoVas, its positive impact on B-NHL needs to be confirmed in larger studies with longer follow-up.

      Abbreviations

      aHR, adjusted hazard ratio; AtMs, atypical memory B cells; BCR, B-cell receptor; CryoVas, cryoglobulinaemic vasculitis; DAA, direct-acting antiviral; DLBCL, diffuse large B-cell lymphoma; FL, follicular lymphoma; HR, hazard ratio; miRNA, microRNA; MZL, marginal zone lymphoma; NHL, non-Hodgkin lymphoma; PFS, progression-free survival; RF, rheumatoid factor; RR, relative risk; SVR, sustained virological response; Tregs, regulatory T cells.

      Financial support

      The authors received no financial support to produce this manuscript.

      Authors' contributions

      Substantial contributions to the conception and design; or the acquisition, analysis, or interpretation of the data: PC, CC, MV. Drafting the article or critical revision for important intellectual content: PC, CC, MV. Final approval of the version to be published: PC, CC, MV, PR, DS.

      Conflict of interest

      Patrice Cacoub declares consultancies, honoraria, advisory board, or speakers’ fees with Abbvie, Alnylam, Bayer, Boehringer Ingelheim, Bristol Myer Squibb, Gilead, Glaxo Smith Kline, Innotech, Mylan, Pfizer, Servier, and Vifor. David Saadoun, Cloé Comarmond, Matheus Vieira, and Paul Régnier have nothing to disclose.
      Please refer to the accompanying ICMJE disclosure forms for further details.

      Supplementary data

      The following are the supplementary data to this article:

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