Abstract
Editor:
Hepatitis G virus (HGV) is a positive-stranded RNA virus belonging to the Flaviviridae family. The diagnosis of acute HGV infection relies on polymerase chain reaction (PCR). Antibodies to the envelope protein 2 (anti-E2) of HGV indicate past infection (1). Intravenous drugs users, poly-transfused patients, and hemodialysis (HD) patients are at risk of acquiring blood-borne infections such as HGV (2,3). Reports concerning to HGV and continuous ambulatory peritoneal dialysis (CAPD) are scarce. The reported prevalence of HGV infection in CAPD patients varies from 0% to 23% (4-6).
We studied 73 patients (58 on HD and 15 on CAPD) with a mean age of 55.7 ± 16.8 years (range 23 – 83 years) and a mean follow-up on dialysis of 61.7 ± 64 months (range 7 – 264 months). Thirty were males and 43 were females. The mean follow-up was 72 ± 69 months for HD patients and 23 ± 12 months for CAPD patients (p < 0.01). The etiology of renal failure was diabetic nephropathy in 10 patients, polycystic kidney disease in 7, vasculitis in 2, chronic glomerulonephritis in 15, nephroangiosclerosis in 7, chronic interstitial nephropathy in 11, amyloidosis in 2, systemic lupus erythematosus in 3, unknown origin in 12, and other causes in 4. We included all patients on HD and all CAPD patients who had never been on HD or transplanted.
The presence of HGV-RNA in serum was studied by a commercially available PCR test (Boehringer–Mannheim, Mannheim, Germany) that includes primers complementary to the NS5 coding region and to the 5’ nontranslated region of the virus genome. Antibodies against the transmembrane E2 protein of the virus were detected in serum by immunoassay (Boehringer–Mannheim).
Anti hepatitis C virus (HCV) antibodies were investigated using a third-generation EIA test (Ortho HCV 3.0 ELISA test system, Chiron Corp., Emeryville, CA, U.S.A.); HCV-RNA was also studied (Cobas Amplicor, Roche Diagnostic Systems, Branchburg, NJ, U.S.A.). HBs Ag and anti-HBc were detected using an automated ELISA test (A5XYM, Abbot Laboratories, Chicago, IL, U.S.A.). The total prevalence of HGV infection (PCR and anti-E2) was 40% (23/58) in HD patients and 13% (2/15) in CAPD patients (p < 0.05). PCR-RNA was detected only in HD patients (8 patients); none of the CAPD patients were PCR-RNA positive. Anti-E2 was found in 17 HD patients (29%) and 2 CAPD patients (13%). Two HD patients were both anti-E2 and PCR-RNA positive.
Twenty-one of 47 (45%) transfused patients were HGV positive (p = 0.008). Twenty-four HD patients had been transplanted before, 3 of them were PCR-RNA positive, 8 were anti-E2-HGV positive, and 13 were HGV negative. Thus, 11 of 24 previously transplanted patients (46%) were HGV positive. Finally, 4 HGV-positive patients (1 PCR-RNA and 3 anti-E2) had never been transfused or transplanted (16%).
HGV was correlated with time on dialysis (p < 0.05). There was no correlation between age or sex and HGV infection.
Eight of 25 HGV patients (32%) showed a mild and transient increase in transaminases.
Twelve patients were HCV positive, all of whom were on HD. All HCV patients were HGV negative (PCR-RNA), thus co-infection with HGV and HCV was absent. However, 5 HCV-positive patients were also anti-E2 positive.
All patients were HBs Ag negative. Anti-HBc was positive in 10 patients (9 HD/1 CAPD), 4 of whom were also anti-E2-HGV positive. Interestingly, no PCR-RNA HGV-positive patient was anti-HBc positive.
In our dialysis unit, HGV infection was more common in HD than in CAPD patients. Our prevalence is similar to that reported by other authors in Europe who consider both PCR-RNA and anti-E2 to be antibodies for HGV infection (3,5,7). Demonstration of infection studying only persistent viremia by PCR underestimates the real prevalence of HGV infection. Patients treated with only CAPD showed prevalence similar to healthy blood donors in Spain (8). The main risk factor for HGV infection was blood transfusion. However, 16% of HGV-positive patients had never been transfused or transplanted, supporting the hypothesis of nosocomial transmission. Similar to other investigators, we did not find co-infection between HGV and HCV. Finally, CAPD could be recommended to young patients included in a renal transplant program since, as with HCV, a higher risk of posttransplantation liver disease was observed among recipients with pre-transplantation HGV infection (9).