New developments in serologic screening of corneal donors for HIV-1 and hepatitis B virus infections

Abstract

Purpose: The authors evaluated different methods to serologically screen potential cadaveric corneal donors for human immunodeficiency virus type 1 (HIV-1) and hepatitis B virus (HBV) infections.

Methods: Three commercially available enzyme-linked immunosorbent assays (ELISAs) for antibodies against HIV-1, a supplemental ELISA test for HIV antigen, and a radioimmunoassay and two ELISAs for hepatitis B surface antigen were compared using serum from cadavers with acquired immune deficiency syndrome (AIDS), cadavers with high risk factors for HIV infection, and cadavers with no known risk of HIV infection, along with respective confirmatory testing.

Results: The ELISA tests for HIV antibodies from Abbott Laboratories, Electro-nucleonics, and Organon-Teknika showed sensitivities of 94.3%, 94.3%, and 97.1%, respectively, compared with the autopsy diagnosis of AIDS in 35 cadavers. The sensitivities of the HIV-1 antibody ELISAs ranged between 73% and 87% compared with positive Western blots in testing 118 sera from cadavers at high risk of HIV-infection, but not manifesting AIDS at the time of death. Supplemental ELISA testing for HIV-1 antigen, in an effort to close the seronegative window, failed to identify any HIV antigen-positive sera confirmed by neutralization that were not also positive for antibodies to HIV-1 by ELISA and Western blot. The ELISA for HBV surface antigen had an overall sensitivity of 92.9% and specificity of only 81.3% compared with radioimmunoassay in testing 409 sera. Monoclonal ELISAs for HIV-1 antigen and HBV surface antigen paradoxically had lower specificity than polyclonal ELISAs, with false positivity correlating with hemolysis and with increasing death to puncture time.

Conclusion: ELISA testing for antibodies against HIV-1 is relatively but not absolutely effective, should be accompanied by historical screening for risk factors, and does not appear to benefit from supplemental ELISA testing for HIV-1 antigen. ELISA testing for HBV surface antigen has lower specificity in screening cadaveric sera when compared with radioimmunoassay.