Objective: To evaluate clinical and biological surrogate markers associated with the presence of B cell non-Hodgkin's lymphoma (B-NHL) in patients with hepatitis C virus (HCV) with mixed cryoglobulinaemia (MC) vasculitis.
Methods: A total of 104 patients with HCV-MC vasculitis (including 20 with B-NHL) were included. The main clinical and biological markers associated with the presence of B-NHL were evaluated.
Results: Patients with B-NHL compared to those without showed higher rates of poor general status (40% vs 16.7%; p = 0.032), purpura (90% vs 66.7%; p = 0.05), renal (50% vs 28.6%; p = 0.11) and cardiac involvement (15% vs 0%; p = 0.0006), higher cryoglobulin levels (1.44 g/litre vs 0.67 g/litre; p = 0.0004), and lower C4 (0.025 g/litre vs 0.06 g/litre; p=0.001) and γ-globulin levels (5.3 g/litre vs 13.3 g/litre; p < 0.0001). The free light chain κ/λ ratio was more frequently abnormal in patients with than without B-NHL (64.3% vs 33.3%, p = 0.10). On multivariate analysis, only γ-globulin level was associated with the presence of B-NHL (OR 0.77 (95% CI -0.44 to -0.13), p = 0.0006). The optimal cut-off value for γ-globulin level was 9 g/litre, with sensitivity, specificity, positive and negative predictive values for the presence of B-NHL of 75%, 82%, 50% and 93%, respectively.
Conclusions: In patients with HCV-MC, a low γ-globulin level (< 9 g/litre) is strongly associated with the presence of B-NHL.