Hepatitis G virus infection in haemodialysed patients: Epidemiology and clinical relevance

Background. The prevalence, incidence, risk factors, and clinical impact of infection by the recently discovered hepatitis G virus (HGV) in haemodialysed (HD) patients, are poorly defined. Methods. All 119 HD patients from two Belgian units selected for their different hepatitis C virus (HCV) prevalences (A: 19.2%, B: 3.4%) were tested for the presence of HGV-RNA, using the reverse transcriptase polymerase chain reaction (RT-PCR) and primers from the 5'-NC and NS 5a genome regions. The results of anti-HCV antibodies and alanine aminotransferase levels (ALT) at the time of RT-PCR, number of transfusions from the onset of HD, and time on HD were retrieved from the medical charts. Forty patients were retested by RT-PCR 3-64 months later. Results. HGV-RNA was detected with both sets of primers in 11/78 patients (14.1%) from centre A and 8/41 patients (19.5%) from centre B, for an average prevalence of 16%. One patient was indeterminate (positive with one set of primers). The presence of HGV-RNA correlated neither with time on HD (P = 0.18), nor with the number of transfusions on HD (P = 0.14). It was associated with the presence of anti-HCV antibodies in centre A (P<0.01) but not B (P>0.5). Twenty-seven initially negative (-) patients (A: n = 18; B: n = 9)were retested: two became positive (+) both in the absence of transfusions for years, giving a yearly incidence of 1.7%. The 13 initially HGV-RNA (+) patients remained so over time (33 patient-years). The presence of HGV-RNA alone does not increase significantly the ALT level, in contrast to the strong influence of HCV. Conclusion. The prevalence and yearly incidence of HGV infection are 16% and 1.7%, respectively, in our HD patients. Neither the number of transfusions on HD nor the time on HD are significant risk factors. Although mixed HCV/HGV infections indicate common risks, the prevalence of HCV in a particular setting does not predict prevalence of HGV. As new infections are detected in the absence of blood transfusions, HGV may be another marker of nosocomial viral transmission. Once acquired, the infection persists for many years in HD patients.