AEGiS-13IAC: Signal-amplificationuboosted ELISA for p24 antigen in heat-denatured plasma is an equivalent low-cost alternative to nucleic acid amplification methods for detection or quantification of HIV-1.

13th International AIDS Conference

Durban, South Africa - July 9-July 14, 2000

Signal-amplificationuboosted ELISA for p24 antigen in heat-denatured plasma is an equivalent low-cost alternative to nucleic acid amplification methods for detection or quantification of HIV-1.

Int Conf AIDS 2000 Jul 9-14; 13:(abstract no. MoOrA107)

Schupbach J, Ledergerber B, Nadal D, Opravil M, Flepp M, Tomasik Z, Boni J
J. Schupbach, Swiss National Center for Retroviruses, University of Zurich, Gloriastrasse 30, CH-8028 Zurich/Switzerland, Switzerland, Tel.: (+41)-1-634-3803, Fax: (+41)-1-634-4965, E-mail: jschupb@immv.unizh.ch

BACKGROUND: HIV load measurement is a prerequirement for the use of any antiretroviral therapy. HIV-1 RNA tests are, however, inaccessible to the majority of infected patients worldwide. It is thus important to provide resource-limited countries with valid alternatives. We have previously demonstrated that two simple modifications, heat-mediated destruction of interfering antibodies and boosting by tyramide signal amplification, confer high sensitivity, specificity and precision to p24 Ag ELISAs.

METHODS: Evaluation of this improved procedure in prospective and retrospective clinical studies.

RESULTS: In real-time analysis over 4 y, infection of 859 samples from 307 infants born to HIV-positive mothers was detected as sensitively by p24 as by PCR for DNA or RNA: 100% sensitivity of all methods after 10 d of age; 99.2% diagnostic specificity of p24 after neutralization (RNA, 98.6%). In 169 infected adults of all stages tested in 1993/94 and followed for 2.7 (0.1-4.9) years, p24 correlated better than RNA with the ensuing CD4 decline. P24 was also a better independent predictor of survival than RNA, while RNA prevailed in predicting clinical AIDS. Treatment-associated changes in p24 and RNA levels in adults and children correlated well. In prospective real-time testing of 12 patients failing under combination therapy, p24 revealed the failure on average 10 to 25 days earlier than RNA (P >.10 resp. *.01). Although slightly more tests were done for p24 than for RNA (mean 3.2 vs. 2.5), costs of p24 testing were 77% less.

CONCLUSIONS: This simple test provides all PCR functions (diagnosis of pediatric HIV infection, prediction of prognosis, viral load monitoring) comparable to or better than PCR and at much lower costs. There is no problem with sample instability or shipping and no need for cumbersome nucleic acid extraction.

Keywords: AEGIS, HIV-1, HIV Core Protein p24, Viral Load, HIV Infections, Enzyme-Linked Immunosorbent Assay, Acquired Immunodeficiency Syndrome, HIV Antigens, Heat, Costs and Cost Analysis, Polymerase Chain Reaction, Antigens, Sensitivity and Specificity, Retrospective Studies, Adult, Child, Human, Infant, methods, immunology, economics
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MoOrA107