Injection drug use facilitates hepatitis C virus infection of peripheral blood mononuclear cells.

Infection of peripheral blood mononuclear cells (PBMCs) with hepatitis C virus (HCV) has been demonstrated and has been found to play a role in relapse of HCV disease and vertical transmission of HCV. Injection drug use is thought to impair function of the immune system and induce tolerance to viruses; therefore, HCV infection of PBMCs could be more likely to occur in injection drug users (IDUs) with HCV infection. Of 108 women who tested negative for human immunodeficiency virus type 1 and positive for HCV RNA, 51 had a history of injection drug use and 57 had no known risk factor for HCV infection. HCV infection was found, by nested reverse-transcription polymerase chain reaction analysis, in the PBMCs of 33 IDUs and of 13 non-IDUs (P=.00003). No correlation was found between infection of the PBMCs and HCV genotype or virus load. Route of transmission and viral factors, as well as immunologic dysfunction, may play a role in viral tropism.