Prevalence of hepatitis C virus infection in B-cell non-Hodgkin's lymphoma: systematic review and meta-analysis.

Background & Aims: The aim of our study was to conduct a systematic review of studies evaluating prevalence of hepatitis C virus (HCV) infection in B-cell non-Hodgkin's lymphoma (B-NHL) and to perform a meta-analysis of case-control studies comparing this prevalence with that of a reference group.

Data Sources: Electronic databases and the Cochrane Controlled Trials Register.

Study Selection: Studies evaluating prevalence of HCV infection in patients with B-NHL. Studies comparing HCV prevalence in B-NHL (cases) and in a reference group (controls) were included in the meta-analysis.

Data Extraction: Author/country, diagnostic method (serology/PCR), control type, matching/design, and VHC prevalence.

Data Synthesis: Prevalence of HCV infection and meta-analysis combining the odds ratios (OR).

Results: Forty-eight studies (5542 patients) were identified. Mean HCV infection prevalence was 13% (95% CI: 12%-14%), which was higher in Italy (20%) and Japan (14%). Ten studies compared HCV prevalence in B-NHL (17%) and healthy controls (1.5%) (OR: 10.8; 95% CI: 7.4-16), results being homogeneous; OR increased up to 14.1 when only Italian studies were considered. Sixteen studies compared HCV prevalence in B-NHL (13%) and in other hematologic malignancies (2.9%) (OR: 4.2; 95% CI: 2.5-7), also with homogeneous results; OR increased up to 7.8 when subanalysis included only Italian studies.

Conclusions: HCV prevalence in patients with B-NHL is approximately 15%, higher than that reported not only in general population (1.5%) but also in patients with other hematologic malignancies (2.9%), suggesting a role of HCV in the etiology of B-NHL. The striking geographic variation in this association suggests that genetic and/or environmental factors are also involved in the pathogenesis of this disorder.