Detection of WA B cells in hepatitis C virus infection: a potential prognostic marker for cryoglobulinemic vasculitis and B cell malignancies.

OBJECTIVE: An uncommon manifestation of hepatitis C virus (HCV) infection is systemic vasculitis associated with type II cryoglobulinemia (cryoglobulinemic vasculitis), a proliferative B cell disorder that transforms into B cell malignancy in 5-10% of patients. The monoclonal rheumatoid factors (mRF) that bear the WA cross-idiotype (Xid) are responsible for most cases of cryoglobulinemic vasculitis in patients with HCV infection. The purpose of this study was to determine whether WA B cells can be detected in asymptomatic patients with HCV infection, using sequence analysis of B cell clonal expansions (BCEs) to identify the WA Xid. METHODS: Asymptomatic patients with HCV infection and those without HCV infection as well as respective control patients with cryoglobulinemic vasculitis, whose serum was either negative or positive for WA mRF, were studied. BCEs were isolated in the patients' blood, and WA BCEs were identified by sequencing analysis. RESULTS: BCEs were detected in all control patients with cryoglobulinemic vasculitis, but only control patients with HCV infection had WA BCEs. None of the 33 asymptomatic patients without HCV infection had a BCE. WA BCEs were detected in 4 (7.4%) of 55 asymptomatic patients with HCV infection, in none of 14 patients with HCV infection and type III cryoglobulinemia, and in 5 (13.5%) of 37 patients with HCV infection and serum RF positivity. One patient with a WA BCE had splenic lymphoma markers and villous lymphocytes, and the villous lymphocytes were found to be WA B cells. CONCLUSION: By identification of the WA Xid, WA B cells can be detected in asymptomatic HCV-infected patients. WA B cells in asymptomatic patients with HCV infection may be a marker for the development of cryoglobulinemic vasculitis and associated B cell malignancies. The results of this study provide a basis for the development of the first practical clinical application of cross-idiotype analysis.

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.

A patient with type II cryoglobulinemic vasculitis and hepatitis C virus (HCV) infection presented with a leukemiclike proliferation of B cells bearing marginal zone B-cell phenotypic markers. A partial trisomy 3 (bands 3q11-29) and overexpression of Bcl-2 without t(14;18) translocation was detected in the monoclonal B cells that were classic rheumatoid factor-producing B cells bearing the WA cross-idiotype. Treatment with interferon-alpha produced a complete clinical remission and synchronous marked decreases in viremia and monoclonal B-cell prevalence. This is the first report of partial trisomy 3 and Bcl-2 overexpression in type II cryoglobulinemic vasculitis associated with HCV infection. Further studies of HCV-infected patients with and without type II cryoglobulinemia are required to determine the prevalence and possible physiologic and/or pathophysiologic significance of these findings.