Hepatitis G and Erythropoietin Therapy in Patients Undergoing Hemodialysis

Accessible online at: http://BioMedNet.com/karger Dear Sir, Hepatitis viruses have become one of the main infectious problems in patients on long-term hemodialysis. A new RNA virus, designated hepatitis G virus (HGV) has recently been identified. The pathogenic relevance of this virus is currently under investigation. Patients on maintenance hemodialysis are at increased risk for HGV infection. Since the prevalence of HGV infection in blood donors is high, blood transfusion could be one of the main factors implicated in HGV transmission in patients on hemodialysis. Regarding hepatitis C virus (HCV) infection, blood transfusion and the length of time on hemodialysis were the main factors involved in HCV transmission to hemodialysis patients in the past [1, 2]. Despite screening of blood products for HCV and the wide use of erythropoietin, which reduces blood transfusion requirements, some patients still become infected with HCV during hemodialysis. Therefore nosocomial transmission of HCV within the hemodialysis units seems to be a factor currently involved in HCV transmission to these patients [1–5]. Recently two studies described presumed hepatitis agents that were designated HGV and GB virus C (GBV-C) [2, 3]. HGV is similar in nucleotide and deduced amino acid sequence to GBV-C and is therefore considered to be a different isolate from the same virus. HGV/GBV-C is an RNA virus with a genomic organization resembling the flaviviridae family and is considered a new genus in this family of virus. HGV/GBV-C seems to establish a chronic infection in humans, is transfusion-transmissible, and has been identified in patients with hepatic disease and groups at risk for exposure to parenterally transmitted infectious agents, such as hemophiliacs, patients with multiple transfused anemia and intravenous drug users. However, there is little information on the prevalence and consequences of HGV infection in patients on long-term hemodialysis. In recently published studies patients on hemodialysis have been shown to be at increased risk for HGV infection [1–5]. Although this virus seems to produce persistent infections, it has not been found to cause liver dysfunction. The aim of this study was to investigate the prevalence of HGV and the effect of erythropoietin therapy in 47 patients with chronic renal failure on a hemodialysis program. These patients (25 men and 22 women, mean age 41.2 years, range 15–71) were screened for HGV. The control group consisted of 54 healthy volunteers (38 women and 16 men, mean age 46.5 B 0.5 years, range 22–74). Serum levels of HGV RNA were measured by reverse transcription polymerase chain reaction. The primary renal disease of the patients was due to chronic glomerulonephritis (25%), diabetes nephropathy (19.5%), pyelonephritis (10%), amyloidosis (14%), polycystic kidney disease (12.5%) and other etiologies (19%). The mean duration of time on hemodialysis was 4.7 B 0.4 years (range 1–16). None of the patients had a history of acute hepatitis after initiation of the hemodialysis program. None of the subjects from the control group showed HGV-RNA, but HGV-RNA was detected in 18 of 47 patients on hemodialysis (38.3%; p ! 0.01). 39 of these 47 patients were treated with erythropoietin and 8 were not. HGV-RNA was found in 15 of 39 patients (38.5%) treated with erythropoietin and in 3 of 8 patients (37.5%) not treated with erythropoietin. There was no correlation between HGV-RNA positivity and erythropoietin therapy (p 1 0.05). Evidence of chronic liver disease was not present in patients infected by HGV, and ALT levels were within normal limits. None of the patients of the erythropoietin-treated group had received blood products for 2 years. The duration of hemodialysis treatment was not different in erythropoietintreated and not treated groups (p 1 0.05). Transfusion of blood products could represent a relevant mechanism of HGV transmission. Although the use of erythropoietin has decreased the transfusion rate of patients on hemodialysis, the results of this study show that patients on maintenance hemodialysis are at increased risk for HGV infection, and erythropoietin treatment did not affect this result. Whether HGV is a cause of viral hepatitis has not been proven yet. However, we cannot declare it an innocent virus either. We must keep HGV under suspicion and under study. Further studies in larger patient groups will clarify the issue.