Long-term impact of superinfection by hepatitis G virus in hepatitis C virus-positive renal transplant patients.

BACKGROUND

The hepatitis G virus (HGV) has been recently cloned. Studies in immunocompetent patients have shown that HGV superinfection in hepatitis C virus (HCV)-positive patients does not affect (i) clinical presentation, HCV RNA level, or response to interferon-alpha therapy; or (ii) the histopathologic severity and characteristics of chronic hepatitis. No data are currently available on the impact of HGV infection on liver histology of renal transplant (RT) patients although the reported prevalence of serum HGV RNA in this population is high, ranging from 14% to 55%.

PATIENTS AND METHODS

We determined the prevalence of HGV infection in 103 HCV-positive RT patients for whom HGV RNA was retrospectively determined by reverse transcription-polymerase chain reaction before, at the time of, and after transplantation (last follow-up). We evaluated the impact of HGV on liver function tests, liver histology (by means of the Knodell score), and renal parameters such as the prevalence of acute rejection and renal function.

RESULTS

A total of 29 (28%) of the HCV-positive RT patients had a positive HGV RNA (group 1). The mean duration of HGV infection was at least 119+/-64 months (range: 18-240 months). Group 1 patients were compared to the 74 HGV RNA-negative/HCV-positive RT patients (group 2). Liver histology showed a significantly lower degree of fibrosis in group 1 (0.4+/-0.5) than in group 2 (1+/-1.2; P=0.02); two patients from group 2 but none from group 1 had overt cirrhosis. Conversely, the extent of hepatic inflammation and hepatocellular destruction was not statistically different between the two groups. The number of patients who experienced at least one acute rejection episode was significantly higher in group 1 (69%) than in group 2 (42%; P=0.01). However, the multivariate analysis did not identify the presence of HGV RNA at the time of renal transplantation as an independent factor of acute rejection; conversely, (i) the occurrence of cytomegalovirus infection or disease and (ii) the duration of HCV infection significantly increased the likelihood of having acute rejection.

CONCLUSIONS

This study shows that: (i) HGV infection was often present when the patients seroconverted for HCV, (ii) HGV RNA-positive/HCV-positive RT patients experienced acute rejection more frequently than HGV RNA-negative/HCV-positive RT patients, and (iii) HGV infection seems to have no detrimental effect upon liver enzymes or liver histology in HCV-positive RT patients.