Diagnosis of HIV-1 infection by PCR with two primer pairs.

We have used two different primer pairs to assess HIV-1 infection of peripheral blood mononuclear cells (PBMC) by polymerase chain reaction (PCR). The study was carried out on 150 individuals: 50 seronegative individuals without risk behaviours for HIV-1 infection, 50 individuals with risk-behaviours but seronegative for HIV-1 and 50 patients with risk-behaviours who were HIV-1 seropositive. Discordances were found between the two primer pairs (SK38/39; SK68/69) in 3 cases. In the non-risk seronegative group, one specimen was scored positive with only one primer pair (SK38/SK39); all the samples belonging to seropositive individuals were found to be positive for HIV-1 DNA using both primer pairs; in the seronegative at risk group 2 samples were positive with only one primer pair (SK38/SK39), and 4 samples were found positive by both primer pairs (SK38/39 & SK68/69). Our study demonstrates that discrepant results take place with relatively high frequency; we propose that all specimens should be tested twice using at least two different primer pairs.