Mixed cryoglobulinemia syndrome (MCs) is a systemic vasculitis characterized by multiple organ involvement due to the vascular deposition of immune-complexes, mainly the cryoglobulins. B-lymphocyte expansion represents the underlying pathological alteration frequently triggered by hepatitis C virus (HCV) infection. The treatment of MCs syndrome is generally based on antiviral drugs and/or immunosuppressors, among which rituximab, an anti-CD20 monoclonal antibody, has been usefully employed for both cutaneous and visceral MCs organ involvement. This multicenter study retrospectively evaluated the effects of rituximab in a large series of patients with active MCs. The observed results were compared to those emerging from the updated review of the literature on this topic. The study included 87 patients (male/female 19/68, mean age 62.3±11.4SD years, mean disease duration 9±6.2SD years, HCV infection in 92% of cases) with active cryoglobulinemic vasculitis evaluated before rituximab monotherapy and after 6-month follow-up by means of main clinico-serological parameters. A PubMed search up to May 31, 2011, was done to find published clinical studies, including case reports of MCs treated with rituximab. A significant clinical improvement was observed in a relevant percentage of cases, regardless the presence/absence of associated HCV infection; namely, complete/partial remission of pre-treatment active manifestations was observed in 74% of skin purpuric lesions, up to 87% of non-healing vasculitic leg ulcers, and 44% of the peripheral neuropathy, mainly paresthesias (patient's visual analogical scale from 62±25 to 37±27; p≤.0001). Moreover, cryoglobulinemic nephropathy, observed in 38 patients, significantly improved in 95% of cases (serum creatinine from 1.8±1.1SD to 1.4±0.8SD mg/dl, p≤.0001; 24-hour proteinuria from 2.2±2.1SD to 0.9±1.7SD g/24h, p≤.0001), with complete remission in the 50%. Among 6 patients with complicating non-Hodgkin's B-cell lymphoma a complete or partial remission was observed in 5/6. A complete remission of abdominal vasculitis was also observed in one patient. These beneficial effects were mirrored by the improvement of cryoglobulinemic serological hallmarks, namely cryocrit and low complement C4, in half cases. The safety of rituximab was confirmed by the small number of side effects recorded during the 6-month follow-up. On the whole, the results of the present study are in keeping with those reported in 39 papers present in world literature, including a total of 279 MCs patients. Rituximab may be regarded as useful and safe pathogenetic treatment of cryoglobulinemic vasculitis. The actual role of this drug should be definitely confirmed by randomized controlled trials, as well as its position in the therapeutical strategy, mainly with respect to antiviral treatment in HCV-associated MCs.

Cryoglobulinemic vasculitis is an immune-complex-mediated systemic vasculitis involving small-medium-sized vessels. A causative role of hepatitis C virus in over 80% patients has been definitively established, with heterogeneous geographical distribution. This review focuses on recent etiopathogenetic, clinico-diagnostic, and therapeutical studies. Hepatitis C virus cannot be integrated into the host genome; it may exert a chronic stimulus to the immune system. The interaction between hepatitis C virus envelope protein E2 with B-cell CD 81 receptor may increase the frequency of VDJ rearrangement in antigen-reactive B lymphocytes. One consequence is the activation of various protooncogenes, including anti-apoptotic Bcl-2. The extended B-cell survival is responsible for autoantibody and immune-complex production, including mixed cryoglobulins; some malignancies, mainly B-cell lymphomas, may complicate cryoglobulinemic vasculitis. Environmental or viral/host genetic cofactors should be relevant in the pathogenesis of hepatitis C virus-related diseases. Cryoglobulinemic vasculitis may overlap with other diseases (systemic vasculitides, Sjögren's syndrome, autoimmune hepatitis, lymphoma), which should be carefully considered for a correct diagnosis and treatment. Cumulative survival of cryoglobulinemic vasculitis is significantly lower compared with the general population. Therapeutic strategies for cryoglobulinemic vasculitis include etiologic (antiviral), pathogenetic (cyclophosfamide, rituximab), or symptomatic (steroids, plasmapheresis) treatments, which should be tailored to the individual patient according to the severity/activity of clinical symptoms. Cryoglobulinemic vasculitis represents a crossroads among autoimmune and lymphoproliferative disorders; as hepatitis C virus infection is the major causative factor, cryoglobulinemic vasculitis is an important model for etiopathogenetic studies of virus-related diseases.

The treatment of systemic sclerosis (SSc) represents a great clinical challenge because of the complex disease pathogenesis including vascular, fibrotic, and immune T- and B-lymphocyte-mediated alterations. Therefore, SSc should be treated by combined or sequential therapies according to prevalent clinico-pathogenetic phenotypes. Some preliminary data suggest that rituximab (RTX) may downregulate the B-cell over expression and correlated immunological abnormalities. Here, we describe a series of 10 SSc patients (4M and 6F, mean age 46±13.5SD years, mean disease duration 6.3±2.7SD years; 5 pts had limited and 5 diffuse SSc cutaneous subset) treated with one or more cycles of RTX (4 weekly infusions of 375mg/m(2)). The main indications to RTX were interstitial lung fibrosis, cutaneous, and/or articular manifestations unresponsive to previous therapies; ongoing treatments remained unchanged in all cases. The effects of RTX were evaluated after 6months of the first cycle and at the end of long-term follow-up period (37±21SD months, range 18-72months). An updated review of the world literature was also done. RTX significantly improved the extent of skin sclerosis in patients with diffuse SSc at 6months evaluation (modified Rodnan skin score from 25±4.3 to 17.2±4.6; p=.022). A clinical improvement of other cutaneous manifestations, namely hypermelanosis (7/7), pruritus (6/8), and calcinosis (3/6) was observed. Moreover, arthritis revealed particularly responsive to RTX showing a clear-cut reduction of swollen and tender joints in 7/8 patients; while lung fibrosis detected in 8/10 remained stable in 6/8 and worsened in 2/8 at the end of follow-up. Pro-inflammatory cytokines, namely IL6, IL15, IL17, and IL23, evaluated in 3 patients with diffuse cutaneous SSc, showed a more or less pronounced reduction after the first RTX cycle. These observations are in keeping with the majority of previous studies including 6 single case reports and 10 SSc series (from 5 to 43 pts), which frequently reported the beneficial effects of RTX on some SSc manifestations, particularly cutaneous sclerosis, along with the improvement/stabilization of lung fibrosis. Possible discrepancies among different clinical studies can be related to the etiopathogenetic complexity of SSc and not secondarily to the patients' selection and disease duration at the time of the study. The present study and previous clinical trials suggest a possible therapeutical role of RTX in SSc, along with its good safety profile. The specific activity of RTX on B-cell-driven autoimmunity might explain its beneficial effects on some particular SSc clinical symptoms, namely the improvement of skin and articular involvement, and possibly the attenuation of lung fibrosis.

The clinical course of chronic hepatitis C virus (HCV) infection is characterized by possible development of both liver and extrahepatic disorders. The tropism of HCV for the lymphoid tissue is responsible for several immune-mediated disorders; a poly-oligoclonal B-lymphocyte expansion, commonly observed in a high proportion of patients with HCV infection, are responsible for the production of different autoantibodies and immune-complexes, such as mixed cryoglobulins. These serological alterations may characterize a variety of autoimmune or neoplastic diseases. Cryoglobulinemic vasculitis due to small-vessel deposition of circulating mixed cryoglobulins is the prototype of HCV-driven immune-mediated and lymphoproliferative disorders; interestingly, in some cases the disease may evolve to frank malignant lymphoma. In addition, HCV shows an oncogenic potential as suggested by several clinico-epidemiological and laboratory studies; in addition to hepatocellular carcinoma that represents the most frequent HCV-related malignancy, a causative role of HCV has been largely demonstrated in a significant percentage of patients with isolated B-cells non-Hodgkin's lymphomas. The same virus may be also involved in the pathogenesis of papillary thyroid cancer, a rare neoplastic condition that may complicate HCV-related thyroid involvement. Patients with HCV infection are frequently asymptomatic or may develop only hepatic alteration, while a limited but clinically relevant number can develop one or more autoimmune and/or neoplastic disorders. Given the large variability of their prevalence among patients' populations from different countries, it is possible to hypothesize a potential role of other co-factors, i.e., genetic and/or environmental, in the pathogenesis of HCV-related extra-hepatic diseases.