Hepatitis C virus infection in patients with non-Hodgkin lymphoma in Thailand

The role of hepatitis C virus (HCV) in the pathogenesis of non-Hodgkin lymphoma (NHL) is controversial.1-3 Germanidis et al4 recently reported in Blood the lack of association of HCV infection and NHL in France, where HCV infection is not common. This is in contrast to the reported high prevalence of HCV infection in patients with NHL (9% to 35%) in Italy5 and North America,6 where HCV infection in normal population is quite frequent (1% to 5%). These results lead to speculation that HCV infection may be associated with NHL only in areas where HCV is highly prevalent.

Thailand has had an increasing incidence of NHL in recent years.7 It also has a high prevalence of HCV infection, averaging 1% to 5% in the general population.8,9 The aim of our study was therefore to determine whether high prevalence of HCV infection exists in our Thai patients with NHL. Ninety-eight patients with intermediate- to high-grade NHL and 32 patients with low-grade NHL seen at Siriraj Hospital were screened for HCV using Cobas Core anti-HCV indirect EIA assay (Roche, Basel, Switzerland) after informed consent. NHL was classified according to working formulation. The Table shows the prevalence of anti-HCV antibody according to NHL subtype.

The overall prevalence of HCV antibody in Thai NHL patients was 2.3%. All patients were HIV-negative and not previously transfused. Only 3 out of 130 cases were HCV-positive including 2 patients with diffuse large-cell lymphoma and 1 patient with follicular mixed small- and large-cell lymphoma. The route of HCV infection in the first 2 patients with intermediate-grade NHL was not clear because no history of blood transfusion or drug abuse could be elicited. The route of viral acquisition in the third patient with low-grade NHL, however, is quite unique because he developed hepatitis after a cut injury occurred while he was performing a surgical procedure in North America. He received interferon treatment for hepatitis and subsequently cleared the virus several years prior to the diagnosis of NHL. PCR for 8 HCV genotypes did not reveal HCV RNA at the time of diagnosis of NHL in Thailand. Whether HCV infection led to the development of NHL in this third patient is unknown. Our overall results, however, do not support the existence of a significant relationship between HCV infection and NHL in Thailand.

NHL in Thailand has a different distribution of histologic subtypes than does the West, with a lower prevalence of low-grade B-cell NHL (averaging 10%).7,10 Whether this may account for the overall low prevalence of HCV infection in NHL in our country is not known. Source and genotype of HCV may play an important role. The predominant HCV genotypes in Thailand appeared to be different from those found in the West.11,12 

In conclusion, although HCV infection is common in Thailand, the majority of Thai NHL patients do not carry the HCV antibody. HCV infection is unlikely to play a major role in the pathogenesis of NHL in Thailand, where HCV infection is highly prevalent.