Background Dendritic cells are the first to encounter HIV-1 at mucosal sites and virus binding occurs via receptors known as DC-SIGN/R. Variations in the number of repeats in the neck region of DC-SIGN/R are reported to possibly influence host susceptibility to HIV-1 infection A single nucleotide polymorphism (SNP) in SDF-1, the natural ligand for the HIV-1 co-receptor CXCR4, is implicated to have protective effects against HIV-1 infection.

Methods The repeat region polymorphisms in DC-SIGN/R by PCR and SNP of SDF1–3’A by PCR-restriction fragment length polymorphism (RFLP) in 230 healthy HIV seronegative individuals, 200 high risk sexually transmitted disease (STD) patients seronegative for HIV and 230 HIV-1 seropositive patients from northern India. The study was approved by the institutional ethics committee.

Results The frequency of homozygous DC-SIGNR 7/7 genotype and allele 7 was significantly higher in patients infected with HIV-1 (P < 0.0001) whereas frequency of heterozygous DC-SIGNR 7/5 genotype and allele 5 was significantly higher in high risk STD patients seronegative (P = 0.003). The heterozygous DC-SIGNR genotypes 7/5 and allele 5 was associated significantly with high CD4⁺ T-cell count and low viral load compared to homozygous DC-SIGNR 7/7 genotype and allele 7 in patients infected with HIV-1. DC-SIGN genotype 7/7 was most frequent in all three groups. A significantly higher frequency of SDF1–3’A/SDF1–3’A was observed in high risk STD patients as compared to HIV seropositive (p = 0.005) and healthy HIV-1 seronegative tested individuals (p = 0.001).

Conclusion The significant higher frequency of heterozygous DC-SIGNR 7/5 and SDF1–3’A genotypes in high risk STD patients and with high CD4⁺T-cell count and low viral load in HIV-1 seropositive patients suggesting the protective role of this genotype in HIV-1 infection.