Antienvelope antibodies are protective against GBV‐C reinfection: Evidence from the liver transplant model

An assay for the detection of antibody against the second envelope (E2) protein of GB virus type C (GBV-C) has been developed. Early reports suggested that this antibody was a marker of viral clearance, yet it is unknown whether anti-E2 is protective against further GBV-C infection. The primary aims were to determine (1) if posttransplantation immunosuppression alters the prevalence of anti-E2; and (2) if anti-E2 positivity pretransplantation protects against acquisition of GBV-C infection posttransplantation. Fifty-four recipients who underwent orthotopic liver transplantation for end-stage liver disease of nonviral etiologies were tested for GBV-C RNA using a PCR-based assay and anti-E2 antibodies by an enzyme-linked immunoassay. Anti-E2 was present in 35% and in 46% of patients pre- and posttransplantation, respectively. Anti-E2 positivity pretransplantation was strongly associated with anti-E2 positivity after transplantation (P < 0.001); 83% of patients with anti-E2 prior to transplantation remained anti-E2-positive after transplantation. A negative association between presence of GBV-C viremia and presence of anti-Ea was found in all patients tested either prior to or following transplantation (P = 0.03). Acquisition of GBV-C infection was significantly tower in patients who were anti-E2-positive prior to transplantation (2/13) compared to those who were anti-E2-negative (12/26) (P = 0.05). It is concluded that immunosuppression does not reduce the prevalence of anti-E2 after transplantation in those who are seroreactive prior to transplantation. Anti-E2 appears to be a neutralizing antibody whose presence at the time of liver transplantation protects against acquisition of GBV-C infection in the peritransplantation period. J. Med. Virol. 56:253-258, 1998. (C) 1998 Wiley-Liss, Inc.