PREDICTIVE MARKERS FOR MOTHER-TO-CHILD TRANSMISSION OF HIV-1 IN DAR-ES-SALAAM, TANZANIA

The aim of this study was to determine immunological factors associate d with increased risk of mother-to-child transmission of HIV-1 that co uld be used as predictive markers in Tanzanian women. One hundred and thirty-eight HIV-1-seropositive and 117-seronegative mothers and their newborns were recruited at delivery and followed up at Muhimbili Medi cal Centre in Dar es Salaam, Tanzania. Blood specimens from the mother s were analyzed for HIV-1 p24 antigen, beta(2)-microglobulin (B2M), T- lymphocyte subsets, and presence of viral DNA in blood mononuclear cel ls by the polymerase chain reaction (PCR). Among 138 seropositive moth ers, 30 (21.7%) had transmitted HIV-1 to their children, as shown by a positive PCR in the child. The vertical transmission rate was signifi cantly higher in women with a percentage of CD4 lymphocytes less than or equal to 20 (eight of 24, 33%) or a level of B2M greater than or eq ual to 2 mg/L (21 of 62, 34%) than in women with a higher percentage o f CD4 lymphocytes (10 of 73, 14%) or a lower level of B2M (eight of 57 , 14%) (p = 0.034 and 0.018, respectively). In eight of 18 (44%) trans mitting mothers the percentage of CD4 lymphocytes was less than or equ al to 20, and in 21 of 29 (72%) transmitting mothers the B2M level was greater than or equal to 2 mg/L. In women with both a low percentage of CD4 lymphocytes (less than or equal to 20) and a high level of B2M (greater than or equal to 2 mg/L), the vertical transmission rate was 54%. Seven of 17 (41%) transmitting mothers had both a low level of CD 4 lymphocytes and a high level of B2M. HIV-1 p24 antigenemia was signi ficantly more common in transmitting than in nontransmitting mothers ( four of 29, 14%, and two of 88, 2.3%, respectively; p = 0.05), but few mothers had this marker. We conclude that a low percentage of CD4 lym phocytes and a high level of B2M, especially when present in combinati on, appear to be useful predictive markers for mother-to-child transmi ssion of HIV-1 in Tanzanian women.