Beta 2-microglobulin, HIV-1 p24 antibody and acid-dissociated HIV-1 p24 antigen levels: predictive markers for vertical transmission of HIV-1 in pregnant Ugandan women.
OBJECTIVE
To evaluate the clinical utility of plasma beta 2-microglobulin (beta 2M) levels, acid-dissociated HIV-1 p24 antigen, and HIV-1 p24-antibody titers in predicting HIV-1 vertical transmission in 227 HIV-1-infected Ugandan pregnant women.


METHODS
Plasma beta 2M levels, acid-dissociated HIV-1 p24-antigen positivity, and HIV-1 p24-antibody titers were determined using commercial enzyme immunoassays (EIA) in a Ugandan cohort of 52 HIV-1-seropositive transmitting mothers, 175 HIV-1-seropositive non-transmitting mothers, and 52 seronegative mothers within 6 weeks prior to delivery.


RESULTS
Transmitter mothers had significantly higher plasma concentrations of beta 2M (1.80 +/- 1.13 mg/l) than non-transmitter seropositive mothers (1.32 +/- 0.81 mg/l; P = 0.0013). Similarly, a significantly higher proportion of transmitter mothers had detectable p24 antigen than non-transmitter mothers [six out of 51 (11.8%) versus six out of 173 (3.5%); P = 0.03]. Compared with the vertical transmission rate of 23% in the seropositive group, the positive predictive values of a beta 2M level > 1.5 mg/l or detectable HIV-1 p24 antigen for vertical transmission were 34 and 50%, respectively. Five of six (83.3%) seropositive mothers with both a beta 2M level > 1.5 mg/l and detectable p24 antigenemia transmitted HIV-1 infection to their infants compared with 25 of 124 (20.2%) seropositive mothers with values below the cut-off values for both tests (P = 0.00249). However, beta 2M was not found to be a significant independent predictor of vertical transmission when analyzed in a multivariate model with p24 antigenemia. There was no significant difference in HIV-1 p24-antibody titers in transmitter mothers versus non-transmitter mothers (P = 0.299).


CONCLUSIONS
beta 2M levels and acid-dissociated HIV-1 p24-antigen assays may be used to predict which HIV-1-infected pregnant women are at greatest risk for vertical transmission. However, only the p24-antigen test was independently predictive of vertical transmission and its clinical utility is limited.
Jackson
J B
JB
Department of Pathology, Case Western Reserve University, Cleveland, OH 44106.
Kataaha
P
P
Hom
D L
DL
Mmiro
F
F
Guay
L
L
Ndugwa
C
C
Marum
L
L
Piwowar
E
E
Brewer
K
K
Toedter
G
G
D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D015331:Cohort Studies; D005069:Evaluation Studies as Topic; D005260:Female; D015483:HIV Antibodies / Q000097:blood*; D016655:HIV Core Protein p24 / Q000032:analysis* / Q000276:immunology; D015658:HIV Infections / Q000453:epidemiology / Q000276:immunology / Q000635:transmission*; D015497:HIV-1 / Q000276:immunology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007124:Immunoenzyme Techniques; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D014454:Uganda / Q000453:epidemiology; D001613:beta 2-Microglobulin / Q000032:analysis*
D015415:Biomarkers; D015483:HIV Antibodies; D016655:HIV Core Protein p24; D001613:beta 2-Microglobulin