Background: The role of hepatitis G virus (HGV) in transfusion-associated infection and its relation to liver disease are not well understood.
Methods: Serum samples collected between 1972 and 1995 from 357 transfusion recipients, 157 controls who did not receive transfusions, 500 randomly selected volunteer blood donors, and 230 donors of blood received by HGV-infected patients were tested for HGV RNA by qualitative and quantitative polymerase-chain-reaction assays. Samples obtained before transfusion and serially after transfusion from 79 of the 81 transfusion recipients who had transfusion-associated non-A, non-B hepatitis were available for testing.
Results: Of the 79 patients with transfusion-associated hepatitis, 63 (80 percent) had infections related to the hepatitis C virus (HCV) and 3 had preexisting HCV and the cause of their acute hepatitis could not be determined; of the remaining 13 patients, 3 had acute HGV infection, and 10 were infected with unidentified agents. Six of the 63 patients with HCV infection who were tested (10 percent) were also infected with HGV. The three patients infected only with HGV had mild hepatitis (mean peak alanine aminotransferase level, 198 U per liter; none had jaundice); the levels of alanine aminotransferase and HGV RNA were not well correlated. The combined HCV and HGV infections were no more severe than HCV infections alone; the alanine aminotransferase values paralleled the levels of HCV RNA, but not those of HGV RNA. There were 35 HGV infections among the 357 transfusion recipients; only 3 had hepatitis with HGV as the sole viral marker. One of the 157 controls and 7 of the 500 randomly selected blood donors (1.4 percent) had detectable HGV RNA. In all eight instances in which a transfusion recipient had acute HGV infection after transfusion and samples from all donors could be tested, at least one HGV-positive donor was identified.
Conclusions: HGV was common in a group of volunteer blood donors, and it can be transmitted by transfusion. Most HGV infections were not associated with hepatitis. HGV did not worsen the course of concurrent HCV infection. No causal relation between HGV and hepatitis has been established.