High prevalence of CXCR4‐using viruses in vertically HIV‐1‐infected infants in Thailand

Abstract

Purpose of the studyPrevious studies evaluating the frequency of CXCR4‐using strains in HIV‐1 vertically infected children restricted mainly to patients infected with subtype B or C strains. However, the coreceptor use by non‐B or non‐C subtypes remains little known, especially in infants. In this study, we determined the HIV‐1 coreceptor usage in infants with vertically‐acquired HIV‐1 infection in Thailand, where the predominant circulating HIV‐1 strains are CRF01_AE and the minority are subtype B.MethodsC2‐V3‐C3 gp120 was amplified in a triplicate nested‐PCR and sequenced. Coreceptor usage was predicted using the geno2pheno [coreceptor] algorithm and analyzed with a false positive rate (FRP) of 10%.Summary of resultsA total of 255 sequences were obtained from viral isolates of 85 HIV‐1‐infected infants (34 male and 51 female) participating in the National AIDS Program (NAP) of the National Health Security Office (NHSO) of Thailand. All children were received ARV prophylaxis according to the Thai national guidelines. The median age was 84 days (range: 33–308). Seventy‐four children (87.1%) were infected with CRF01_AE strain and 11 (12.9%) were infected with subtype B strain. Concordance in tropism prediction for the triplicates was observed in all samples. CXCR4 coreceptor‐using strains were found in 44.7% (38 of 85) and CCR5 coreceptor‐using strains were found in 55.3% (47 of 85). No significant difference in age (p=0.34) and clinical signs of AIDS (p=0.47) were observed between these populations. CCR5Delta32 and CCR5m303 mutation genotypes that may contribute to a selective pressure of viruses to alternatively use CXCR4 as a coreceptor were not found.ConclusionsA high prevalence of HIV‐1 CXCR4‐using variants was found among HIV‐1 vertically infected infants in Thailand, indicating that a direct vertical transmission of CXCR4‐using variants or a rapid switch from CCR5‐using to CXCR4‐using viruses shortly after transmission. These observations may have implications for clinical and therapeutic aspects, especially in the early stage of HIV‐1 infection in infants and may benefits for using of CCR5‐antagonists in this population.