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

OBJECTIVE

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.

DESIGN

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.

RESULTS

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.

CONCLUSIONS

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.

What kind of hepatitis?

Finding one major hepatotropic virus may not be enough to identify the aetiology of liver disease when risk factors are present, particularly in patients with past or present infection with other viral agents, or chronic liver disease. The pathogenic process in these cases is often complex. In the five cases we report, acute hepatitis (initiated by halothane, cytomegalovirus or Epstein-Barr virus) preceded the reactivation of hepatitis B infection, and these events occurred in patients with chronic hepatitis C infection. Each case demonstrates how several viruses can be implicated in the development of hepatitis, either as single agents or via cross-activation of T cells. The nosography of hepatitis, therefore, and the optimum therapeutic choices, can puzzle the clinical team.

Elevated alanine aminotransferase in blood donors: role of different factors and multiple viral infections

Many different aetiological agents stimulate alanine aminotransferase (ALT) production. Viral markers and other aetiologies were investigated in 2166 individuals, randomly selected from 10,000 consecutive blood donors. Elevation of ALT was found in 10.8% of subjects. Grouping donors according to ALT level and correlating with, respectively, hepatitis B core antibody (HBcAb), cytomegalovirus antibody alone, or associated with HBcAb, showed similar findings (high ALT 11.1%, normal 11.6%; high 85.4%, normal 81.4%; high 10.2%, normal 11.0%, respectively). Hepatitis C virus (HCV) antibody was found to be significantly associated with elevated ALT levels (high 1.7%, normal 0.26%). Other causes of ALT elevation were alcohol abuse (17%), obesity (25%) and dyslipidaemia (38%), but in 11% there was no obvious aetiology. Although HCV is a rare cause of elevated ALT in blood donors, it seems to be the only virus, among those tested, to account for liver damage. This may be due to the non-protective role of HCV antibody, the low specificity of ALT, or the pathogenic role of uninvestigated viruses.

Liver pathology in cytomegalovirus infection associated with hepatitis B virus

A retrospective study was carried out in 56 patients to establish the association of cytomegalovirus (CMV) with active or inactive hepatitis B virus (HBV) infection as a possible risk factor in the development of severe liver disease. Patients with positive CMV serology and active or inactive HBV infection had elevated alanine aminotransferase activity and had a relatively high incidence of more severe lesions (chronic hepatitis and active cirrhosis). In the absence of CMV, only one case of cirrhosis was identified compared with seven cases of hepatic fibrosis. By analogy with hepatitis C virus, CMV may bring about activation of the host inflammatory response against hepatocytes following HBV infection, resulting in the development of severe hepatitic disease.

Prevalence and significance of HCV infection in a consecutive series of patients with HBV antibodies and raised aminotransferases

Fifty-one patients with signs of past HBV infection were investigated for the HCV virus antibody. All patients were at least HBsAb, HBcAb positive. Two groups were selected: patients with increased serum AST activity (32/51) and patients with normal serum AST activity (19/51). Prevalence of HCV infection was higher (81.2%) in the group with high serum aminotransferases as compared to that found in the second group (31.6%) (p less than 0.002). Furthermore, histological findings showed higher prevalence of HCV infection in patients with cirrhosis as compared to patients with hepatic fibrosis. Results show that lack of clinical remission in patients with past HBV infection could be due to the presence of HCV, thus representing an unrecognized cause of "cryptogenetic" liver diseases.