EVALUATION OF EPIDEMIOLOGIC AND SEROLOGICAL PREDICTORS OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 (HIV-1) INFECTION AMONG HIGH-RISK PROFESSIONAL BLOOD-DONORS WITH WESTERN-BLOT INDETERMINATE RESULTS

Background: Indeterminate pattern of results in Western blot (WBI) for human immunodeficiency virus type-1 (HIV-1) infection may represent e arly HIV-1 infection or may be non-specific in origin. This issue can be resolved by follow up testing upto at least 6 months resulting in p sychological distress as well as in high drop out rates among those un dergoing investigation pointing out the need for additional parameters that could help in determining the status of HIV-1 infection at the t ime of initial testing itself in individuals with WBI pattern. Objecti ve: The objectives of the present study were: (i) to determine the fre quency of HIV-1 infected individuals in a group of professional donors showing WBI patterns in initial testing on the basis of follow up ser ological studies; (ii) to find out if any HIV related epidemiological or serological characteristics recorded at the time of initial testing could be considered as predictor for HIV-1 infection in WBI specimens ; and (iii) to evaluate two alternative serodiagnostic strategies for HIV-1 infection viz. multiple EIAs based on different antigen preparat ions/principles and a line immunoassay (LIA) employing recombinant ant igens in resolving status of HIV-1 infection in specimens showing WBI results at initial testing. Study design: Professional donors with WBI patterns belonging to EIA reactive and EIA nonreactive groups were su bjected to study of epidemiological profile, prevalence of sexually tr ansmitted diseases (STD) markers and follow up serological testing for HIV-1 at 6, 12, 24 and 48 weeks intervals to record any seroconversio n. The initial and follow up specimens from the donors with initial WB I results were subjected to two EIAs (one based on dot immunoassay usi ng synthetic HIV-1 antigens and other based on microwell EIA using rec ombinant HIV-1 proteins) as well as to LIA. Results: Professional dono rs with initial WBI results, from the EIA reactive group had higher pr oportion of unmarried individuals (90.3%), with history of heterosexua l promiscuity (75%) and visit to STD clinics (36.1%) compared with the WBI donors from the EIA nonreactive group (72.7, 42.4 and 12.1%, resp ectively, P values < 0.001). Prevalence of antitreponemal antibodies w as higher in the former group (16.7%) compared with the later group (1 .5%, P value < 0.002). Seroconversion was recorded in 4 (7.3%) out of 55 EIA reactive WBI donors from the EIA reactive group that were chara cterised by high optical density (OD) values in EIA, 'p24 only' patter n of band in WE and positivity by LIA at the time of initial testing. LIA was found to be more reliable test compared with combination of EI As to determine status of HIV-1 infection in WBI specimens at the time of initial testing. Conclusion: The present study points out that par ameters like history of heterosexual promiscuity, prevalence of STD ma rkers, high OD values in screening EIA, 'p24' only pattern of bands in WE and positivity by LIA could have individual predictive values for HIV-1 infection in specimens showing WBI pattern of results at initial testing. (C) 1998 Elsevier Science B.V. All rights reserved.