Open AccessPerformance of a Modified HIV-1 p24 Antigen Assay for Early Diagnosis of HIV-1 Infection in Infants and Prediction of Mother-to-Infant Transmission of HIV-1 in Dar es Salaam, Tanzania
Author(s) -
Eligius Lyamuya,
Ulla Bredberg-Rådén,
Augustine Massawe,
Ernest J.N. Urassa,
G. Kawo,
Georgina Msemo,
Theodora Kazimoto,
A. Östborn,
Katarina Karlsson,
Fred Mhalu,
Gunnel Biberfeld
Publication year - 1996
Publication title -
journal of acquired immune deficiency syndromes and human retrovirology
Language(s) - English
Resource type - Journals
eISSN - 2331-6993
pISSN - 1077-9450
DOI - 10.1097/00042560-199608010-00014
Subject(s) - dar es salaam , medicine , human immunodeficiency virus (hiv) , antigen , transmission (telecommunications) , polymerase chain reaction , virology , tanzania , immunology , biology , gene , biochemistry , environmental science , environmental planning , electrical engineering , engineering
The aim of this study was to determine the utility of an amplified human immunodeficiency virus type 1 (HIV-1) p24 antigen (ag) assay using heated plasma or serum samples for the early diagnosis of HIV-1 infection in infants and for the prediction of the risk of mother-to-infant (MTI) transmission of HIV-1 in Dar es Salaam, Tanzania. The study included 125 samples from 76 infants positive for HIV-1 DNA by the polymerase chain reaction (PCR), 106 samples from 101 PCR-negative infants and 116 and 160 samples from seropositive and seronegative mothers, respectively. Samples were boiled to dissociate immune complexes and tested for HIV-1 p24 ag using a p24 ag amplification assay. Reactive samples were confirmed by a neutralization assay. Altogether, 123 of 125 samples from 76 PCR-positive infants were positive for p24 ag (sensitivity = 98.7%). HIV-1 p24 ag was found in all 18 samples collected at 1-8 weeks, in 35 of 36 samples collected at 9-26 weeks, in all 40 samples collected at 27-52 weeks, and in 30 of 31 samples collected > 52 weeks after birth. Detection of HIV-1 p24 ag was significantly more common in transmitting mothers (12 of 29, 41.4%) than in nontransmitting mothers (nine of 87, 10.3%) (p < 0.001). Among mothers with p24 antigenemia, the vertical transmission rate was significantly higher (12 of 21, 57%) than in mothers without p24 antigenemia (17 of 95, 18%) (p < 0.001). All samples from 101 PCR-negative children and 160 seronegative mothers were negative for p24 ag (specificity = 100%). We conclude that using heated plasma or serum increases the sensitivity of the p24 ag assay significantly. This modified simple test may be sufficient for the early diagnosis of HIV-1 infection in infants in settings with limited laboratory facilities. It is also useful for prediction of the risk of MTI transmission of HIV-1.