Background The French Red Cross has instituted a program for the Prevention of Mother-To-Child HIV-1 Transmission (PTMT) in Pointe-Noire, Congo. A reliable and low-cost method was needed for the early diagnosis of neonatal infection. The aim of this study was to assess the feasability of plasma HIV-1 RNA detection using real-time PCR to diagnose neonatal HIV-1 infection in Pointe Noire, Congo.

Methods Real-time PCR technology was set up in April 2003 in the serology lab of the HIV Day Care Center in Pointe-Noire. The real-time RT-PCR was performed using the ANRS protocol (Taqman assay in LTR gene with Abi Prism 7000). HIV-1 RNA quantification was performed in reference to an external standard curve (10 fold dilutions of an HIV-1 strain). Blood was sampled in children at 1 and 3 months of age and 2 months after weaning (in breast-fed children). The plasma HIV RNA test was done prospectively using both real-time PCR in Pointe Noire and the Roche test in Paris, France.

Results The sensivity threshold of the real-time PCR was estimated at 1,000 copies/ml using 0.2 mL of plasma. 122 samples  were tested in 82 children (73 at 1 month; 46 at 3 months; 3 2 months after weaning). Eight children were found to be HIV-RNA-positive by real-time PCR (6 at 1 month of age, 2 subsequently in breast-fed children). These 8 samples were also found positive by the Roche test. The median viral load was 6.2 log copies/mL. The mean difference between the real-time PCR and the Roche quantitative results was 0.3 log. HIV-1 infection was confirmed in these children by subsequent samples. The sensitivity of real-time PCR was therefore 100% (95%CI: >77-100%). 114 samples of 74 children were found negative by real time PCR, 82 of these samples also underwent the Roche test and were all found negative. The specificity of real-time PCR was 100% (95%CI: >97 to 100%).

Conclusion This study confirms the feasibility of neonatal HIV-1 diagnosis using real-time PCR technology in a Congolese lab without previous experience in molecular biology. Real time PCR enabled early, rapid, sensitive and specific diagnosis and performed as well as available commercial tests. Once the machine has been purchased, cost of real-time PCR is moderate (US ₁0 per test), allowing for its extensive use in PTMT programs in developing countries.

Keywords: neonate; developing countries; real-time PCR