Hepatitis C virus infection is significantly associated with malignant lymphoma in Taiwan, particularly with nodal and splenic marginal zone lymphomas.

Aims: Hepatitis C virus (HCV) is a hepatotropic and lymphotropic RNA virus causally linked to lymphoma with a strong geographic variation. The aim of this study was to investigate the association of HCV and lymphoma in Taiwan, in which HCV is endemic.
Methods: Patients diagnosed with lymphoma from January 2004 to December 2008 were investigated for serum anti-HCV, and the infection rate was compared with that in healthy controls. Various lymphoma types were investigated for HCV infection. Immunohistochemistry was performed for HCV non-structural (NS)3 protein, and genotyping was performed by reverse transcriptase PCR.
Results: Thirty-eight (11.0%) of 346 patients with lymphoma were positive for anti-HCV, as compared with 15 (1.8%) of 824 healthy controls (p<0.001, chi(2) test) with an age-adjusted and sex-adjusted OR of 4.57 (95% CI 2.41 to 8.68). Only nodal (five of eight cases) and splenic (two of two cases) marginal zone lymphomas (MZLs) as a group were significantly associated with HCV, as compared with mucosa-associated lymphoid tissue (MALT) lymphomas (1 of 15; p=0.002, Fisher's exact test). All 26 anti-HCV-positive cases stained for HCV-NS3 were negative. The most common genotypes were 1b (22%) and 2a (56%), with no statistical difference from 203 patients with HCV-related chronic liver disease.
Conclusions: The incidence of HCV infection among lymphoma patients in Taiwan was significantly higher than that for healthy controls. Furthermore, non-MALT (nodal and splenic) MZL was the only group significantly associated with HCV. A larger national study is warranted to re-confirm our findings and to elucidate if any particular HCV genotypes were related to the pathogenesis of lymphoma.