To the Editor:
Cases of lymphocytic monoclonal B-cell proliferation such as non-Hodgkin's lymphomas have been reported in chronically hepatitis C virus (HCV)-infected patients. Lymphomas of the mucosa-associated lymphoid tissue (MALT) type are due to monoclonal proliferation of B cells showing characteristic histopathological features of MALT. Luppi et al1 recently reported an unexpectedly high prevalence of HCV infection in a series of patients with low-grade lymphomas of the MALT type in various body sites. This study showed the presence of both anti-HCV antibodies and HCV-RNA in the serum of 8 of 16 MALT lymphoma patients (50%).1 In another study, Pioltelli et al2 also observed a high prevalence of HCV infection in low-grade lymphomas of the MALT type (36.4%), although they did not mention the number of cases examined.
The aim of the present study was to assess the prevalence of HCV infection in a well-characterized series of 46 patients with gastric MALT lymphoma. Of the 46 patients, 25 had a low-grade lymphoma (14 women, 11 men, mean age 54.2 years, range 30 to 75) and 21 had a high-grade lymphoma (8 women, 13 men, mean age 56.3 years, range 23 to 85). Helicobacter pylori infection was demonstrated by serological and/or histological tests in 37 of 46 patients (80.4%). One hundred sixty-five patients with gastroduodenal disease were recruited to compose the control group. There were 84 patients with duodenal ulcer, 43 with gastric ulcer, and 38 with dyspepsia. The two groups were comparable in terms of the sex ratio, age, prevalence of H pylori, risk factors for HCV infection (previous parenteral exposure to blood products, intravenous drug misuse, nosocomial exposure), and geographical origin. Diagnosis of gastric MALT lymphoma was based on gastric biopsy specimens evaluated according to Isaacson's classification3 and by immunophenotypic analysis of surface T- and B-lymphocyte markers. Anti-HCV antibodies were determined by third-generation enzyme-linked immunosorbent assay and confirmed by third-generation recombinant immunoblot assay (RIBA) in all patients (Ortho Clinical Systems, Raritan, NJ). There was no significant difference between the prevalence of HCV infection in the MALT lymphoma group and the control group: among the patients with gastric MALT lymphoma, only 1 had anti-HCV antibodies (2.2%), compared with 4 in the control group (2.4%) (not significant). The only MALT patient who tested anti-HCV Ab-positive was also positive forH pylori and belonged to the low-grade MALT lymphoma group.
Thus, we found no higher prevalence of HCV infection among patients with gastric MALT lymphoma than in a control group composed of subjects with a gastroduodenal disease similarly related to H pyloriinfection, with the same risk factors for hepatitis C and deriving from the same geographical region. Our data contrast with those of the Italian teams1,2 and are more in keeping with those of the American and British teams,4,5 who did not specifically study gastric MALT lymphoma but found no evidence of a relationship between HCV infection and non-Hodgkin's lymphoma.
To our knowledge, this is the first study to evaluate the prevalence of HCV infection in a large, well-characterized series of patients with gastric lymphomas of the MALT type. Our results indicate that there is no link between HCV infection and gastric MALT lymphoma in France.