HIV type 1 diversity in northern Paris, France

During a 6-month period, we studied the diversity of HIV-1 subtypes in 392 adult patients seen in Bichat-Claude Bernard Hospital, northern Paris, France. All the samples were serotyped and a subset was genotyped by means of HMA. Serotyping was performed with a new peptide subtype-specific EIA (SSEIA), based on in vitro competition for antibody binding between the representative V3 peptides of the different clades (A to E). HMA with plasmids from clades A to H gave unambiguous results on 105 of the 116 samples tested. The agreement between SSEIA and HMA was 36/41 for subtype B, 2/2 for subtype D, and 4/5 for subtype E. We found a discrepancy in the results between clade A and C: the patients with sera reacting to peptide C were confirmed by HMA as being infected by clade A strains. Three patients reactive with peptide A were infected by a subtype F. These results indicate that peptide cross-reactivity, even in the SSEIA format, hinders serotyping. In 11 samples, all from African patients, the subtype remained indeterminate because PCR or HMA failed. Caucasian patients (n = 223) were mainly infected by subtype B. HMA and/or SSEIA revealed non-subtype B infection in 14 Caucasians, who were infected by the sexual route overseas or in France. Patients originating from other countries (mainly in Africa) exhibited a broad strain diversity, with most of the different subtypes so far described being represented. This study confirms the frequency of subtype B strains in Caucasians living in France, but emphasizes the emergence of the different HIV-1 subtypes in Paris, together with the extent of strain trafficking. Discordances between serotype and genotype assays confirm that both tests require additional development.