Interferon alfa-2a therapy in cryoglobulinemia associated with hepatitis C virus

Infection and vasculitis

Vasculitis may be associated with infection, immunization or anti-microbial drugs. Infections are responsible for a number of different types of vasculitis. Conversely, patients with vasculitis may develop infections, which sometimes mimic relapse. The aim of this review is to summarize the various aspects of the inter-relationship between vasculitis and infection, and the physiopathological mechanisms involved, in light of our current knowledge from animal models. Currently, a causal relationship between infection and vasculitis has only been established in a few instances and many mechanisms remain hypothetical. This inter-relationship is further assessed from the point of view of clinical presentation and therapeutic options, based on case reports and prospective observational data.

EULAR recommendations for the management of primary small and medium vessel vasculitis

OBJECTIVES

To develop European League Against Rheumatism (EULAR) recommendations for the management of small and medium vessel vasculitis.

METHODS

An expert group (consisting of 10 rheumatologists, 3 nephrologists, 2 immunologists, 2 internists representing 8 European countries and the USA, a clinical epidemiologist and a representative from a drug regulatory agency) identified 10 topics for a systematic literature search using a modified Delphi technique. In accordance with standardised EULAR operating procedures, recommendations were derived for the management of small and medium vessel vasculitis. In the absence of evidence, recommendations were formulated on the basis of a consensus opinion.

RESULTS

In all, 15 recommendations were made for the management of small and medium vessel vasculitis. The strength of recommendations was restricted by low quality of evidence and by EULAR standardised operating procedures.

CONCLUSIONS

On the basis of evidence and expert consensus, recommendations have been made for the evaluation, investigation, treatment and monitoring of patients with small and medium vessel vasculitis for use in everyday clinical practice.

Hepatitis C infection and chronic renal diseases

More than 170 million people worldwide are chronically infected with the hepatitis C virus (HCV), which is responsible for over 1 million deaths resulting from cirrhosis and liver cancers. Extrahepatic manifestations are also relevant and include mixed cryoglobulinemia, lymphoproliferative disorders, and kidney disease. HCV infection is both a cause and a complication of chronic kidney disease, occurring largely in the context of mixed cryoglobulinemia. This infection also represents a major medical and epidemiologic challenge in patients with end-stage renal disease on renal replacement therapy with dialysis or transplantation. In these settings the presence of HCV correlates with higher rates of patient mortality than in HCV-negative subjects on dialysis or undergoing kidney transplant. The major concern is the lack of safe and effective drugs to treat HCV-infected patients with chronic kidney disease. Unfortunately, there are no large-scale clinical trials in this population, especially those receiving renal replacement therapy, so that strong evidence for treatment recommendations is scant. This review article provides the readers with the most recent insights on HCV infection both as cause and complication of chronic kidney disease, discusses pitfalls and limitations of current therapies, and reports on preliminary experience with novel therapeutic agents, as well as directions for future research.

Hepatitis C virus infection induced vasculitis

Cryoglobulinemia are immune complexes that may induce systemic cryoglobulinemic vasculitis, a small-vessel vasculitis involving the skin, the joints, the peripheral nerve system, and the kidneys. During the last 15 years, progresses have been done after the discovery of the hepatitis C virus, the main cause of cryoglobulins. Main factors associated with cryoglobulin production are female gender, alcohol intake above 50 g/day, extensive liver fibrosis, and steatosis. Symptomatic cryoglobulins (i.e., vasculitis) are associated with older age, longer duration of infection, and main characteristics of cryoglobulin (type II, IgM kappa, high serum levels). The physiopathology is complex, and it involves humoral immunity, B- and T-cellular immunity but not the virus itself. Peg-Interféron alpha Ribavirine combination leads to a virological and clinical response of the vasculitis in about 70% of patients. In nonresponders, recent open series suggested the efficacy of Rituximab with a good response in up to 80% of patients but a relapse in 42% after 7 months after the last infusion. For future prospects and projects, new therapeutic strategies include a combination of best antiviral treatment with Peg-Interferon plus Ribavirin and Rituximab. Multicenter controlled trials are mandatory.

Hepatitis C virus and kidney disease

Hepatitis C virus (HCV) infection remains frequent in patients on renal replacement therapy and has an adverse impact on survival in infected patients on chronic hemodialysis as well as renal transplant (RT) recipients. Nosocomial spread of HCV within dialysis units continues to occur. HCV is also implicated in the pathogenesis of renal dysfunction often mediated by cryoglobulins leading to chronic kidney disease as well as impairing renal allograft function. The role of antiviral therapy for hepatitis C in patients with renal failure remains unclear. Monotherapy with conventional interferon (IFN) for chronic hepatitis C is probably more effective in dialysis than in non-uraemic patients but tolerance is lower. Limited data only are available about monotherapy with pegylated interferon and combination therapy (pegylated IFN plus ribavirin) for chronic HCV in the dialysis population. Clinical experience with antiviral therapy for acute HCV in dialysis population is encouraging. Interferon remains contraindicated post-RT because of concerns about precipitating graft dysfunction. Sustained viral responses obtained by antiviral therapy in renal transplant candidates are durable after renal transplantation and may reduce HCV-related complications after RT (post-transplant diabetes mellitus, HCV-related glomerulonephritis, and chronic allograft nephropathy).

Extrahepatic hepatitis C virus after transplantation: diabetes and renal dysfunction

1. Insulin resistance is associated with hepatitis C virus infection and plays a role in the progression of hepatitis C virus-related liver disease and fibrosis. 2. Treating insulin resistance and achieving glycemic control will be important for improving post-liver transplant morbidity and mortality: control of the hepatitis C virus will help to accomplish this. 3. The main renal complication of hepatitis C virus is membranoproliferative glomerulonephritis, and this occurs most commonly in the setting of mixed cryoglobulinemia.

Mixed cryoglobulinemia

Mixed cryoglobulinemia (MC), type II and type III, refers to the presence of circulating cryoprecipitable immune complexes in the serum and manifests clinically by a classical triad of purpura, weakness and arthralgias. It is considered to be a rare disorder, but its true prevalence remains unknown. The disease is more common in Southern Europe than in Northern Europe or Northern America. The prevalence of 'essential' MC is reported as approximately 1:100,000 (with a female-to-male ratio 3:1), but this term is now used to refer to a minority of MC patients only. MC is characterized by variable organ involvement including skin lesions (orthostatic purpura, ulcers), chronic hepatitis, membranoproliferative glomerulonephritis, peripheral neuropathy, diffuse vasculitis, and, less frequently, interstitial lung involvement and endocrine disorders. Some patients may develop lymphatic and hepatic malignancies, usually as a late complication. MC may be associated with numerous infectious or immunological diseases. When isolated, MC may represent a distinct disease, the so-called 'essential' MC. The etiopathogenesis of MC is not completely understood. Hepatitis C virus (HCV) infection is suggested to play a causative role, with the contribution of genetic and/or environmental factors. Moreover, MC may be associated with other infectious agents or immunological disorders, such as human immunodeficiency virus (HIV) infection or primary Sjögren's syndrome. Diagnosis is based on clinical and laboratory findings. Circulating mixed cryoglobulins, low C4 levels and orthostatic skin purpura are the hallmarks of the disease. Leukocytoclastic vasculitis involving medium- and, more often, small-sized blood vessels is the typical pathological finding, easily detectable by means of skin biopsy of recent vasculitic lesions. Differential diagnoses include a wide range of systemic, infectious and neoplastic disorders, mainly autoimmune hepatitis, Sjögren's syndrome, polyarthritis, and B-cell lymphomas. The first-line treatment of MC should focus on eradication of HCV by combined interferon-ribavirin treatment. Pathogenetic treatments (immunosuppressors, corticosteroids, and/or plasmapheresis) should be tailored to each patient according to the progression and severity of the clinical manifestations. Long-term monitoring is recommended in all MC patients to assure timely diagnosis and treatment of the life-threatening complications. The overall prognosis is poorer in patients with renal disease, liver failure, lymphoproliferative disease and malignancies.

Cryoglobulinemia and renal disease

PURPOSE OF REVIEW

Cryoglobulinemia occurs in a variety of clinical settings including lymphoproliferative disorders, infection and autoimmune disease. The worldwide pandemic of hepatitis C virus infection has resulted in a significant increase in its extrahepatic complications including cryoglobulinemia and renal disease. Here we review the types of cryoglobulins, mechanisms of cryoglobulin formation, links between hepatitis C virus and renal disease, and current approaches to therapy.

RECENT FINDINGS

The prevalence of cryoglobulinemia in hepatitis C virus-infected individuals is surprisingly large and may be found in more than 50% of some infected subpopulations. Most of these patients will not have overt renal disease, but there is a population of unknown size of patients with subclinical glomerular disease that has the potential to become clinically significant. In cases of hepatitis C virus-associated cryoglobulinemia, treatment remains focused on eradication of viremia, but interventions directed at B lymphocytes are increasingly utilized. The mechanisms of cryoglobulin formation and renal injury remain largely obscure, but recent evidence implicates the innate immune system in the initiation of disease.

SUMMARY

The most common renal injury associated with hepatitis C virus infection, in patients both with and without evidence of cryoglobulinemia, is membranoproliferative glomerulonephritis. There has been increasing focus on defining the mechanisms that link these processes and the evolution of renal injury in all clinical settings of cryoglobulinemia.

Extrahepatic manifestations of hepatitis C virus infection

Hepatitis C virus may cause hepatic and extrahepatic diseases. Extrahepatic manifestations range from disorders for which a significant association with viral infection is supported by epidemiologic and pathogenetic data, to anecdotal observations without clear proof of causality. This article describes the diagnosis and treatment of these diseases.

Treatment of hepatitis C-associated mixed cryoglobulinemia vasculitis

PURPOSE OF REVIEW

Hepatitis C virus infection is the main cause of mixed cryoglobulinemia vasculitis. The disease expression of mixed cryoglobulinemia vasculitis is variable, ranging from mild clinical symptoms (purpura, arthralgia) to fulminant life-threatening complications (glomerulonephritis, widespread vasculitis). Treatment of hepatitis C virus-mixed cryoglobulinemia vasculitis may target either the viral trigger (hepatitis C virus) or the downstream B-cell arm of autoimmunity. This review focuses on recent advances in our understanding of the treatment of hepatitis C virus-mixed cryoglobulinemia vasculitis.

RECENT FINDINGS

Aggressive antiviral therapy with Peg-IFNalpha and ribavirin should be considered as induction therapy for hepatitis C virus-mixed cryoglobulinemia vasculitis with mild to moderate disease severity and activity. In patients presenting with severe disease, an induction phase of immunosuppression is often necessary while awaiting the generally slow response to antiviral treatments. Combination therapy with rituximab and Peg-IFNalpha plus ribavirin appears logical as it may target both the viral trigger (hepatitis C virus) and cryoglobulin-producing B-cells.

SUMMARY

Antiviral therapy and rituximab are the main therapeutic options in hepatitis C virus-mixed cryoglobulinemia vasculitis. Further studies are needed to better define the therapeutic strategy.

Protein therapeutics: a summary and pharmacological classification

Once a rarely used subset of medical treatments, protein therapeutics have increased dramatically in number and frequency of use since the introduction of the first recombinant protein therapeutic--human insulin--25 years ago. Protein therapeutics already have a significant role in almost every field of medicine, but this role is still only in its infancy. This article overviews some of the key characteristics of protein therapeutics, summarizes the more than 130 protein therapeutics used currently and suggests a new classification of these proteins according to their pharmacological action.

[Chronic viral hepatitis and kidney failure]

Chronic viral hepatitis remains a major problem among patients with chronic renal failure. Hepatitis B and C viruses are frequent among dialysis patients and after renal transplantation and may significantly diminish the survival of both the patient and the graft. Hepatitis B and C viral infection in these patients is often characterized by normal transaminase levels despite viremia and progressive liver lesions. Liver biopsy remains essential for assessing the extent of liver disease. Cirrhosis is a contraindication to transplantation of only a kidney, because of elevated morbidity and mortality. A combined as liver-kidney transplantation may be considered. The best treatment of hepatitis infections is preventive: vaccination against the hepatitis B virus and attentive hygiene, especially to prevent nosocomial transmission. Among patients not awaiting transplant, antiviral treatment should be reserved for patients with active or even fibrotic liver disease. For hemodialysis patients awaiting kidney transplant: Alpha interferon is ineffective and poorly tolerated by dialysis patients. Lamivudine is effective and well tolerated, but its long-term efficacy and its optimal effective dose in dialysis patients remain unknown.

Anti-CD20 monoclonal antibody (rituximab) treatment for cryoglobulinemic vasculitis: where do we stand?

Mixed cryoglobulinemia (MC) vasculitis represents a complication of the B cell response to a variety of chronic inflammatory diseases. Recent reports describe the use of monoclonal antibodies directed to CD20 antigen (rituximab), a transmembrane protein expressed on pre-B lymphocytes and mature lymphocytes. The goal of this article is therefore to review published data in order to better analyse the efficacy and tolerance of rituximab treatment in patients with MC vasculitis. After systematic review of the literature and exclusion of review papers, 13 manuscripts were identified that reported on a total number of 57 cases of MC secondary to hepatitis C virus (HCV) infection (75.4%) or essential mixed cryoglobulinemia (24.6%). Previous treatments failed to control the main signs of vasculitis; these were either HCV (n = 37) or immunomodulating treatments. Most patients (48 out of 57) received four weekly consecutive intravenous infusions of 375 mg/m(2) of rituximab. The duration of follow-up after rituximab therapy was 9.7 months. Rituximab infusions had great efficacy on the main vasculitis signs, with a clinical response in 80-93% patients. A relapse of MC was noted in 14 out of 36 (39%) patients. A relatively small number of side effects were reported. We conclude that rituximab therapy for patients with mixed cryoglobulinemia vasculitis, HCV-induced or essential, shows great efficacy on the main vasculitis signs in the majority of reported patients. A relapse of cryoglobulinemia vasculitis was frequently noted. Randomised controlled trials with long-term study are needed to form definitive conclusions on the benefit/risk ratio of rituximab therapy in such patients.

Therapeutic control of hepatitis C virus: the role of neutralizing monoclonal antibodies

Liver failure associated with hepatitis C virus (HCV) accounts for a substantial portion of liver transplantation. Although current therapy helps some patients with chronic HCV infection, adverse side effects and a high relapse rate are major problems. These problems are compounded in liver transplant recipients as reinfection occurs shortly after transplantation. One approach to control reinfection is the combined use of specific antivirals together with HCV-specific antibodies. Indeed, a number of human and mouse monoclonal antibodies to conformational and linear epitopes on HCV envelope proteins are potential candidates, since they have high virus neutralization potency and are directed to epitopes conserved across diverse HCV genotypes. However, a greater understanding of the factors contributing to virus escape and the role of lipoproteins in masking virion surface domains involved in virus entry will be required to help define those protective determinants most likely to give broad protection. An approach to immune escape is potentially caused by viral infection of immune cells leading to the induction hypermutation of the immunoglobulin gene in B cells. These effects may contribute to HCV persistence and B cell lymphoproliferative diseases.

Hepatitis C virus and lymphoma

Hepatitis C virus (HCV) is well known for its aetiological role in chronic non-A, non-B viral hepatitis, liver cirrhosis and hepatocellular carcinoma; in addition, the virus has also been implicated in a number of extra-hepatic "autoimmune" disease manifestations. A causative association between HCV and non-Hodgkin lymphoma (NHL) was postulated relatively recently and has been the subject of intense investigation, as well as some debate. On the strength of epidemiological data, emerging biological investigations and clinical observations, HCV appears to be involved in the pathogenesis of at least a proportion of patients with NHL. Morphologically, HCV-associated lymphomas represent a variety of histological subtypes including marginal zone lymphoma (splenic, nodal and extranodal), small lymphocytic lymphoma/chronic lymphocytic leukaemia, lymphoplasmacytic lymphoma and diffuse large B-cell lymphoma. Remarkably, some HCV-associated NHL appears to be highly responsive to antiviral therapy, providing some clinical evidence for this relationship, as well as the prospect for novel therapeutic intervention.

Update on the use of biologics in primary systemic vasculitides

The introduction of biologic therapies, which selectively target components of the immune system, has revolutionized the treatment of rheumatoid arthritis. Anti-TNF-alpha therapy (infliximab, etanercept and adalimumab) and B-cell-depleting agents, such as rituximab, are the most widely used agents. Increased experience of the use of biologic drugs in other immune-mediated inflammatory diseases has led to the application of biologic therapies in the treatment of primary systemic vasculitis. Conversely, the success of biological agents has improved understanding of the immunopathogenesis of vascular inflammation. The need for biologic agents arises from the failure of the current standard of care to maintain remission while limiting drug toxicity. Evidence for the efficacy of biologic agents does not match that of conventional immunosuppressants yet, but it is building rapidly. This paper reviews the current evidence for the standard of care of patients with vasculitis and the role of biologic therapy in primary systemic vasculitis. In this review, we examine the rationale for using biologics based on the pathophysiology of primary systemic vasculitis. The risks and benefits of the use of biologics are discussed, together with future directions and predictions of these emerging therapies.

Treatment of HCV in patients with renal failure

There continues to be a high prevalence of hepatitis C virus infection in patients with chronic kidney disease (CKD) on maintenance hemodialysis, despite screening of blood products and precautions to prevent the transmission of viral hepatitis within dialysis units. In addition, an increased rate of mortality from liver disease has been observed in infected patients on long-term dialysis, despite the frequent absence of biochemical dysfunction. Hepatitis C-infected renal transplant recipients have diminished patient and graft survivals compared to uninfected controls. Treatment with interferon in renal transplant candidates has resulted in sustained viral responses that have been long lasting even after subsequent renal transplant. A major concern limiting the use of interferon following renal transplant is graft dysfunction due to rejection. Ribavirin's induction of hemolytic anemia is the major reason why it is avoided in patients with CKD. Cautious use of reduced-dose ribavirin in small studies has been promising in these patients with close monitoring of hematocrit and additional measures to enhance compensatory erythropoiesis.

Infection and glomerulonephritis

Glomerular injury, occurring either as primary glomerular disease or as part of a systemic disease process, is usually a result of immune-mediated mechanisms. The morphologic reaction pattern has a diverse spectrum of appearance, ranging from normal by light microscopy in minimal change disease to crescentic forms of glomerulonephritis, with conspicuous disruption of the normal glomerular morphology. The mechanisms of glomerular immune deposit formation include trapping of circulating antigen-antibody complexes and the in situ formation of immune complexes within the glomerulus. While the majority of postinfectious immune-complex-mediated glomerulonephritides are believed to result from the deposition of circulating antigen-antibody complexes, preformed outside of the kidney and secondarily deposited in the kidney, the notion of forming in situ antigen-antibody complexes to either planted antigens or to integral structural components of the glomerulus, through "cross-reacting" autoimmune reactions, is gaining popularity in a variety of forms of glomerulonephritides. Patients with HIV infection may develop a spectrum of renal pathology, the glomerular manifestations of which include both antigen-antibody complex and nonimmune-complex-mediated pathogenetic mechanisms. Similarly, patients with Streptococcal infections, Hepatitis B virus, or Hepatitis C virus infection may develop a spectrum of glomerulonephritides, which are predominantly immune-complex-mediated. Therapy for glomerular diseases due to HIV, hepatitis B, or C virus infections remains a challenge.

Etiologic treatment of hepatitis C virus-associated mixed cryoglobulinemia

The treatment of mixed cryoglobulinemia (MC) includes several drugs--steroids, cyclosporins, colchicine, plasmapheresis--but given the documented association between MC and hepatitis C virus (HCV), the treatment of choice seems to be antiviral therapy. Several authors have reported the efficacy of interferon (IFN) alpha in the inhibition of HCV replication and reduction of cryoglobulin levels. The therapy with IFN as monotherapy in MC shows a complete response rate in only 10 -12% of cases. Complete response to therapy using a combination of IFN plus ribavirin varies in different studies from 18% to 64% of cases. There are only two studies on the treatment of MC with peginterferon plus ribavirin. Both studies, given the high number of complete responders, reinforce the idea that peginterferon plus ribavirin is, at present, the best available treatment for cryoglobulinemic syndrome. The results obtained with peginterferon combined therapy are superior to standard interferon plus ribavirin in treatment-naive patients. In fact, a sustained virological response was observed in 44% of patients; the same results were obtained for clinical (purpura and arthralgia disappearance) and biochemical (aminotransaminases normalization) responses. New drug combinations, like peginterferons plus anti-CD20 antibodies, should be considered for treatment of MC in the future.

Approach to vasculitic neuropathies

Since vasculitic neuropathy is treatable and potentially debilitating, clinicians should develop an approach to neuropathy that increases the likelihood of uncovering existing systemic or nonsystemic vasculitis. The presence of a connective tissue disease, systemic vasculitis, asymmetric or non--length-dependent axonal polyneuropathy, or multiple axonal mononeuropathies should heighten suspicion, but vasculitic neuropathy can also present as a distal symmetric polyneuropathy with or without other organ involvement. Electrodiagnostic testing utilizing extensive nerve conductions may be helpful in identifying features suggestive of vasculitic neuropathy and in selecting an abnormal nerve and muscle for biopsy confirmation. An array of laboratory tests may lead to identification of a systemic disorder that is either characterized by or predisposes to vasculitic neuropathy. The mainstays of treatment are corticosteroids and cyclophosphamide, but other drugs are used in specific conditions. With early diagnosis and careful monitoring of treatment regimens, the prognosis is usually good.

B-cell depletion in the treatment of mixed cryoglobulinemia

A controlled study has been carried out to assess the efficacy of rituximab (RTX), a chimeric antibody that binds to the B-cell surface antigen CD20, in twenty patients with mixed cryoglobulinemia (MC) and HCV-positive chronic active liver disease, resistant to interferon-alpha (IFN-alpha) therapy. They received an intravenous infusion of 375 mg/m(2) RTX once a week for 4 consecutive weeks. Infusion of RTX had a good safety profile, and no severe side-effects were reported. Sixteen patients (80%) had a complete response (CR), characterized by rapid improvement of clinical signs (disappearance of purpura, weakness, arthralgias and improvement of peripheral neuropathy), and decreased cryocrit. CR was associated with a significant reduction in rheumatoid factor (RF) activity and anti-HCV antibody titers. Decline of IgG anti-HCV titers in the cryoprecipitates was usually associated with a favorable response (r= 0.81; p <0.005). No differences in the dynamics of B-cell depletion and recovery were found between responders and non-responders. Molecular monitoring of the B-cell response revealed disappearance/deletion of peripheral clones in the responders and great stability in the non-responders. RTX had a deep impact on hepatitis C viremia: HCV RNA increased to approximately twice the baseline level in the responders, whereas it remained much the same in the non-responders. Twelve out of 16 responders (75%) remained in remission throughout the follow-up. The results indicate that RTX has clinical and biological activity in HCV-positive MC patients. However, in view of the increased viremia in the responders, additional modes of application and combination of RTX with other agents need to be investigated.

Efficacy of low-dose rituximab for mixed cryoglobulinemia

Rituximab at 375 mg/m(2) x 4 is effective for refractory HCV-related mixed cryoglobulinemia. We conducted a pilot study to assess the efficacy of a lower dosage, 250 mg/m(2) x 2. Six consecutive patients with mixed cryoglobulinemia were treated. All patients had severe or life-threatening disease manifestations, including necrotizing skin ulcers, renal disease, hyperviscosity or intestinal vasculitis. Four of five evaluable patients (excluding one early death) had >80% decrease of cryocrit and remission of vasculitis at the end of a 22- to 55-week (median 40) follow-up. The non-responder failed to respond to additional rituximab treatment, suggesting intrinsic resistance rather than insufficient dosage as the cause of treatment failure. No sustained increase of HCV viremia after rituximab was observed. Rituximab at 250 mg/m(2) x 2 may be as effective as at 375 mg/m(2) x 4 for treating mixed cryoglobulinemia. Larger studies are required to assess the efficacy of low-dose rituximab.

Outpatient assessment of systemic vasculitis

The vasculitides are complex, multisystem diseases, the natural history of which has been transformed by the use of immunosuppressive therapy. In many cases, survival is characterized by the presence of ongoing low-grade disease activity and, now that patients can survive acute, life-threatening manifestations of vasculitis, the new challenge is to provide accurate descriptions of these problems so as to plan appropriate changes in therapy to ensure optimal control of disease, with minimal toxicity, damage, and impairment of function. To achieve these aims, it is necessary to undertake structured evaluation of patients, with a significant dependence on careful clinical observation, supported by appropriate laboratory investigation at all stages from diagnosis to long-term care of these patients. This chapter reviews the important aspects of disease assessment and recommends a strategy for managing these complex patients. We can make use of standardized disease assessment instruments, such as the Birmingham Vasculitis Assessment Score and the Vasculitis Damage Index, to serve as an aide memoire in documenting the clinical features of disease. Routine monitoring for drug toxicity in the short-term and long-term is essential. Above all, however, it is very important to review these patients regularly and see them urgently in case of flares or complications, which are a common problem in most forms of vasculitis.

Cryoglobulinemia

Cryoglobulinemia refers to the presence in serum of immunoglobulins that precipitate at a cold temperature. Type I cryoglobulins are single monoclonal immunoglobulins usually associated with haematological disorders. Types II and III are mixed cryoglobulins, composed of monoclonal or polyclonal IgM respectively, having rheumatoid factor activity that bind to polyclonal immunoglobulins. Mixed cryoglobulinemia (MC) syndrome is a consequence of immune-complex mediated vasculitis and is characterized by a typical clinical triad: purpura, weakness, arthralgias; many organs particularly kidney and peripheral nervous system may be involved. MC may be associated with infectious and systemic disorders and since 1990 studies have demonstrated that hepatitis C virus (HCV) may be considered the principal trigger of the disease. The relation between MC and HCV infection shows new insights in the interpretation of the link between viral infection, autoimmune phenomena and lymphoproliferative disorders evolution. In fact, the virus chronically stimulates B-cell polyclonal proliferation from which a monoclonal population may emerge. In symptomatic patients with HCV related MC therapeutic strategy should include an attempt at viral eradication. Antiviral therapy may also be effective in determining the regression of B-cell lymphoproliferative disorder. Rituximab could represent a safe and effective alternative to standard immunosuppression and exerts selective B-cell control.

Hepatitis C virus-related lymphoproliferative disorders: An overview

Hepatitis C virus (HCV) is a global health problem affecting 3% of the world's population (about 180 million) and a cause of both hepatic and extrahepatic diseases. B-cell lymphoproliferative disorders, whose prototype is mixed cryoglobulinemia, represent the most closely related as well as the most investigated HCV-related extrahepatic disorder. The association between extrahepatic (lymphoma) as well as hepatic malignancies (hepatocellular carcinoma) has justified the inclusion of HCV among human cancer viruses. HCV-associated manifestations also include porphyria cutanea tarda, lichen planus, nephropathies, thyreopathies, sicca syndrome, idiopathic pulmonary fibrosis, diabetes, chronic polyarthritis, sexual dysfunctions, cardiopathy/atherosclerosis, and psychopathological disorders. A pathogenetic link between HCV virus and some lymphoproliferative disorders was confirmed by their responsiveness to antiviral therapy, which is now considered the first choice treatment. The aim of the present paper is to provide an overview of extrahepatic manifestations of HCV infection with particular attention to B-cell lymphoproliferative disorders. Available pathogenetic hypotheses and suggestions about the most appropriate, currently available, therapeutic approaches will also be discussed.

Cryoglobulinemia related to hepatitis C virus infection

A causal link among hepatitis C virus (HCV) infection and essential mixed cryoglobulinemia, cryoglobulinemic glomerulonephritis, and vasculitis is strongly supported. HCV triggers autoimmune response in predisposed individuals that manifests as organ-specific and non-organ-specific autoantibodies and as polyclonal/monoclonal rheumatoid factor, which has a central role in causing damaging cryoglobulin and immune complex tissue levels. Immunologic events are mainly induced by HCV infection persistence, with excessive immune stimulation. Humoral immune dysfunction leads to autoantibodies and rheumatoid factor production with cryoglobulinemia, glomerulonephritis, vasculitis, neuropathy, and probably thyroiditis, and arthritis in rare cases. Cellular immune dysfunction leads to lymphocytic infiltration, proliferation, and cytokine production. Pegylated (or not) interferon-alpha in combination with ribavirin appears to be the treatment of choice for patients with symptomatic essential mixed cryoglobulinemia with or without glomerulonephritis. Novel treatment with rituximab is promising.

Severe hepatitis C virus-related cryoglobulinaemic sensory-motor polyneuropathy treated with pegylated interferon-a2b and ribavirin: clinical, laboratory and neurophysiological study

BACKGROUND/AIMS

Severe involvement of central and/or peripheral nervous system is a rare complication of hepatitis C virus (HCV)-related cryoglobulinaemia.

METHOD

Four patients with HCV-related type II/III cryoglobulinaemia (three males with genotype 1, one female with genotype 3) who presented with severe sensory-motor polyneuropathy, one with central nervous system involvement as well, were treated with pegylated IFNa-2b 1.5 microg/kg/week and ribavirin 10.6 mg/kg/daily for 48 weeks. Neurological evaluation involved detailed clinical motor and sensory scores/scales and neurophysiological studies before and after treatment.

RESULTS/CONCLUSION

Three out of four patients had undetectable serum HCV-RNA, normal levels of aminotransferases and substantially lower or undetectable levels of cryoglobulins at the end of treatment and at 24 weeks follow-up period. Treatment was well tolerated and all patients exhibited significant improvement of neuropathy based on solid clinical and laboratory criteria that was associated with the virological response.

Cryoglobulinemia in chronic hepatitis C: clinical aspects and response to treatment with interferon alpha and ribavirin

INTRODUCTION: The main extra-hepatic manifestation of hepatitis C is mixed cryoglobulinemia (MC). The aim of this study was to evaluate its prevalence among patients with chronic hepatitis C (CHC), to correlate its presence to host and virological variables and to the response to combined therapy with interferon-alpha and ribavirin. CASUISTIC AND METHODS: 202 CHC naive patients (136 with chronic hepatitis and 66 with cirrhosis) were consecutively evaluated for the presence of cryoglobulins. Cryoprecipitates were characterized by immunoelectrophoresis and classified according to the Brouet's criteria. RESULTS: The prevalence of MC was 27% (54/202), and 24% of them (13/54) showed major clinical manifestation of the disease. Even though type III MC was more frequent (78%), symptomatic MC was more common in type II MC. The presence of cirrhosis (RR = 2.073; IC95% = 1.029 - 4.179; p = 0.041), and age of the patients (RR = 1.035; IC95% = 1.008 - 1.062; p = 0.01) were independently associated with the presence of cryoglobulins. No relationship was found with viral load and genotype. 102 patients were treated with interferon alpha and ribavirin. Among these, 31 had MC. Sustained virological response (around 30%) was similar in patients with and without MC (p = 0.971). CONCLUSION: MC represents a prevalent complication in patients with CHC, specially older and cirrhotic patients. Only 24% of these patients show clinical manifestation of the disease, specially those with type II MC. The presence of MC did not affect the response to therapy.

The kidney transplant recipient with hepatitis C infection: pre- and posttransplantation treatment

Liver disease secondary to chronic hepatitis C virus (HCV) infection is an important cause of morbidity and mortality in dialysis patients and kidney transplant recipients. Evaluation of patients with chronic HCV infection is warranted to determine stage of disease and the need for HCV therapy. Although combination therapy with interferon (IFN) plus ribavirin is the standard of care for chronic HCV infection, IFN monotherapy is recommended in dialysis patients because ribavirin is contraindicated in the presence of renal failure. The goals of pretransplantation HCV therapy are to decrease the risk for progression of HCV-associated liver disease, stabilize renal function in patients with HCV-related glomerulopathy, and prevent development of HCV-associated renal disease after transplantation. Posttransplantation HCV therapy is generally not recommended because of concerns regarding risk for precipitating acute rejection; however, antiviral therapy may be indicated to treat HCV-related glomerulopathy or prevent progression of chronic hepatitis C in patients with more advanced stages of fibrosis. When treatment is required, restored renal function allows use of combination therapy with IFN and ribavirin. Limitations of current HCV therapy include lack of tolerability and suboptimal response rates. New antiviral agents that can be used in dialysis patients (e.g., ribavirin alternatives) and in the posttransplantation setting (e.g., IFN alternatives) are needed to improve outcomes in these populations.

Dermatologic disorders associated with chronic hepatitis C: effect of interferon therapy

Chronic hepatitis C virus infection (HCV) is associated with extrahepatic manifestations, including such dermatologic conditions as mixed cryoglobulinemia, porphyria cutanea tarda, and lichen planus. Patients with chronic HCV and extrahepatic manifestations are often excluded from clinical trials evaluating interferon (IFN) therapy due to concerns about poor response, adverse events, and toxicity. Thus, data regarding the efficacy of IFN not only on the underlying chronic HCV, but also on extrahepatic manifestations, are limited in these patients. Case reports suggest that the response of dermatologic extrahepatic manifestations to IFN in patients with chronic HCV is highly variable. This review summarizes available data on dermatologic conditions associated with chronic HCV and their response to IFN therapy.