Prevalence of monoclonal gammopathies in patients with hepatitis C virus infection

Background: An association between monoclonal gammopathies and chronic liver diseases has been reported. Objective: To determine the prevalence of monoclonal gammopathies in patients with chronic hepatitis C virus (HCV) infection and the possible association of monoclonal gammopathies with HCV genotypes. Design: Prospective study. Setting: Departments of internal medicine and hematology at two university hospitals in Italy. Patients: 239 HCV-positive and 98 HCV-negative patients with chronic liver diseases were recruited consecutively. Measurements: Clinical data were gathered, liver histologic examination was done, serum immunoglobulin and cryoglobulin levels were measured, and immunoelectrophoresis was done for monoclonal component detection. Patients with monoclonal gammopathy had serum HCV RNA measured and HCV genotype determined by polymerase chain reaction and had histologic examination of bone marrow. Results: Monoclonal band was detected in 11% of HCV-positive patients and in 1% of HCV-negative patients (P = 0.004). The prevalence of HCV genotype 2a/c was higher in patients with monoclonal gammopathies than in those without (50% compared with 18%; P = 0.009). Conclusion: The prevalence of monoclonal gammopathies in patients with HCV-related chronic liver disease is striking and is often associated with genotype 2a/c infection.