Longterm course of mixed cryoglobulinemia in patients infected with hepatitis C virus

OBJECTIVE: To describe epidemiological, clinical, and immunological characteristics and the longterm course of persistent mixed cryoglobulinemia (MC) in patients infected with hepatitis C virus (HCV). METHODS: Retrospective study of HCV infected patients (HCV RNA positive) who had persistent positive MC, with 2 immunochemical typings of MC carried out after 24-month minimum interval. RESULTS: In total, 125 patients were studied, aged 52 +/- 13 years at diagnosis of MC, with duration of HCV infection of 18 +/- 10 years. At entry, 60 patients had type II MC, 53 patients had type III, and 12 patients had the oligoclonal type. At the second immunochemical typing, after a mean interval of 45 +/- 20 months, MC was type II in 72 patients, type III in 39 patients, and the oligoclonal type in 14 patients. The proportion of cases of MC with the same immunochemical type was higher among patients with type II (78%) than type III (59%) or oligoclonal MC (17%) (p < 0.01). The MC that changed turned more to type II (55.5%) than type III (29%) or the oligoclonal type (15.5%) (p = 0.0002). MC vasculitis (purpura, arthralgia, peripheral neuropathy, renal involvement) and other extrahepatic manifestations (polyarteritis nodosa, lymphoma) in 60/125 patients was associated with advanced age (p < 0.01), a longer duration of infection (p < 0.05), type II MC (odds ratio = 5, p < 0.01), and a higher MC serum level (p < 0.01). CONCLUSION: During chronic active HCV infection, type II MC is more stable over time than type III and oligoclonal MC. The oligoclonal type appears to be an intermediate stage in the course of type III changing to type II MC. Symptomatic persistent HCV MC was associated with advanced age, longer duration of HCV infection, type II MC, and a higher MC serum level.