TRANSMISSION OF HIV-1 IN INFANTS BORN TO SEROPOSITIVE MOTHERS - PCR-AMPLIFIED PROVIRAL DNA DETECTED BY FLOW CYTOMETRIC ANALYSIS OF IMMUNOREACTIVE BEADS

The diagnosis of HIV infection in newborns is established by amplifica tion of proviral DNA using the polymerase chain reaction (PCR). We dev eloped a nonisotopic method for heminested PCR using a biotinylated pr imer among sets of three oligonucleotides, each selected from the HIV long terminal repeat (LTR) and gag sequences. An internal probe incorp orating digoxigenin-dUTP was also synthesized by PCR. The PCR products , hybridized with LTR region or gag region probes, were captured with streptavidin-coated magnetic beads and detected by fluorescein isothio -cyanate-labeled antidigoxigenin in flow cytometric analysis. This imm unoreactive bead assay (PCR-IRB) detected about three copies of HIV pr oviral DNA. A panel of 50 coded DNA specimens of infants previously as sayed by conventional PCR and with known clinical results revealed tha t the PCR-IRB findings using LTR, but not gag, were in agreement. A do uble-blind prospective study of blood samples from 14 mother-infant pa irs using the PCR-IRB amplification of LTR gave results similar to the commercial Amplicor HIV-1 PCR test and were consistent with the clini cal outcomes. PCR-IRB results were positive for Ii mothers and three i nfants, one at birth, one at 2 weeks after birth, and one at 8 weeks a fter birth. PCR-IRB is a simple, reliable, specific, and automatable a ssay useful in the early diagnosis of perinatal HIV infection in clini cal practice and regional screening programs.