Multiple viral infections in a group of intravenous drug users: hepatitis B virus exposure is the risk factor

Infection with hepatotropic viruses is associated with a variable degree of liver disease, and there is evidence that more severe lesions are related to the association with another viral infection. The aim of this investigation is to establish the relationship between different viral infections occurring in the same individual and the presence and progression of liver disease.

The study population comprises 754 intravenous (IV) drug abusers exposed to hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV) or cytomegalovirus (CMV). All individuals were followed for an average of 2 years. Liver disease was assessed by liver function tests, 99m-technetium (99mTc) liver scintigraphy, and also by liver biopsy in a subset (n = 136) of patients. The different viral patterns and presence of disease were analysed by logistic regression, and the risk factors were calculated. Contingency tables of patients with single or associated infections were drawn up to evaluate progression of liver disease.

Association of HIV with at least one other viral infection was constant. Surface antigens of HBV (HBsAg) were always associated with HIV (n = 19); in this group, 18 patients had signs of liver disease. A past infection with HBV, as revealed by the presence of at least antibodies against the surface antigen (HBsAb) and antibodies against the core antigen of HBV (HBcAb), was detected in 463 patients (61.4%). The overall prevalence of HCV antibodies was 63.91% (n = 482). In 96.8% of the 406 patients tested, HCV-RNA was detected by reverse transcriptase polymerase chain reaction (RT-PCR). The majority of patients with high alanine transaminase (ALT) had anti-HBV antibodies in the presence of HCV (56.1%). At the end of follow-up, all of these patients showed signs of active liver disease, and scoring was significantly worse than in patients with either HBV or HCV alone. An infection/reactivation of CMV was found in patients previously exposed to HBV and with increased ALT values.

Data emerging from this study reveal the association of HCV or CMV, or both, with a previous HBV infection, as demonstrated by HBsAb and HBcAb, and rapid progression of the disease in this group of patients. A previous HBV infection therefore appears to be an important risk factor for subsequent viral-related liver disease.