DIRECT-DETECTION OF PROVIRAL GAG SEGMENT OF HUMAN-IMMUNODEFICIENCY-VIRUS IN PERIPHERAL-BLOOD LYMPHOCYTES BY COLORIMETRIC PCR ASSAY AS A CLINICAL LABORATORY TOOL APPLIED TO DIFFERENT AT-RISK POPULATIONS

We used a colorimetric polymerase chain reaction (PCR)-based assay in kit form to detect directly human immunodeficiency virus type 1 (HIV-1 ) proviral gag sequences in peripheral blood cells from 68 healthy blo od donors, 51 subjects at risk for HIV infection, 122 patients with HI V-1 infection, 11 patients with indeterminate Western blot (immunoblot ) results, 4 blood donors HIV-1 positive by enzyme immunoassay, and 13 children born to HIV-1-seropositive mothers. The results obtained in the blood donors and HIV-1-infected patients demonstrated the high deg ree of diagnostic Specificity and sensitivity of the PCR method. HIV-1 infection was excluded in 10 of the 11 patients with indeterminate We stern blot results and in all four enzyme immunoassay-positive blood d onors. A diagnosis of HIV infection was ruled out by negative PCR resu lts in 5 of 13 children from seropositive mothers, which excluded vert ical transmission of the infection in these cases; these children were younger than 3 months and had positive serological results. Two at-ri sk patients with negative serological results had positive PCR results . All results were confirmed by conventional PCR. In conclusion, color imetric PCR, which is commercially available in kit form, is an easy a nd reliable technique that can be used to detect proviral HIV-1 genome s in blood cells, and despite the limitations owing to HIV genome vari ability, it is useful in the clinical setting for the diagnosis of HIV infection in selected categories of patients.