Detection of antibodies to E2-protein of GB virus-C/hepatitis G virus in patients with acute posttransfusion hepatitis.

GB virus-C/hepatitis G virus (GBV-C/HGV) is an RNA virus that can be transmitted by transfusion with the diagnosis based on the detection of serum GBV-C/HGV RNA by reverse transcription-polymerase chain reaction. In order to evaluate the role of antibodies to the E2 protein (anti-E2) of GBV-C/HGV in patients with acute posttransfusion hepatitis, anti-E2 was measured in one patient with acute GBV-C/HGV infection, five patients with acute GBV-C/HGV and hepatitis C virus (HCV) coinfection, and four patients with positive pretransfusion GBV-C/HGV RNA who were superinfected with HCV after transfusion. One patient with acute GBV-C/HGV infection remained GBV-C/HGV RNA-positive 18 months after transfusion and did not develop anti-E2. Among five patients with acute GBV-C/HGV and HCV coinfection, one lost GBV-C/HGV RNA 28 months after transfusion and developed anti-E2 independent of serum alanine aminotransferase levels. The other four patients remained GBV-C/HGV RNA-positive and anti-E2-negative at the end of follow-up. Among four patients with positive pretransfusion GBV-C/HGV RNA and super-infected with HCV, one lost GBV-C/HGV RNA 2 months and one 10 months after superinfection and subsequently developed anti-E2. The other two patients remained GBV-C/HGV RNA-positive without anti-E2 at the end of follow-up. Sixty-five samples tested were mutually and exclusively positive for either GBV-C/HGV RNA or anti-E2; only one sample was positive for both GBV-C/HGV RNA and anti-E2. In conclusion, the development of anti-E2 of GBV-C/HGV usually indicates the clearance of serum GBV-C/HGV RNA in patients with acute posttransfusion hepatitis.