Stromal cell-derived factor 1 polymorphism in patients infected with HIV and implications for AIDS progression in Tunisia

Background: An interesting finding in the epidemiology of human immunodeficiency virus (HIV) infection is that certain mutations in genes coding for chemokines, and their receptors and ligands, may confer resistance or susceptibility to HIV-1 infection and acquired immunodeficiency syndrome (AIDS) progression. The mutation most frequently studied is stromal cell-derived factor (SDF) 1-3' A, a single nucleotide polymorphism in the 3' untranslated region at the 801 position of the SDF1 gene, which seems to be associated with susceptibility or resistance to diseases, including AIDS. We examined the frequency of the above polymorphisms in the Tunisian population, and evaluated their contribution to a protective genetic background against HIV infection and progression. Methods and materials: One hundred forty blood samples from HIV-infected patients from the Cellular Immunology Research Laboratory at the National Blood Transfusion Center were compared with those of 164 random blood donors from the same center. Genotyping was initially performed by polymerase chain reaction (PCR) analysis. SDF1 PCR product genomic regions were further subjected to restriction fragment length polymorphism analysis for genotype determination. Screening for the SDF1 polymorphism in the HIV-infected population yielded 56 heterozygous (40%), 52 mutation homozygous (37.1%), and 32 wild-type homozygous (22.8%) subjects. In contrast, in our healthy population, we found 70/164 heterozygous (42.6%), nine mutation homozygous (5.4%), and 85 wild-type homozygous (51.8%) subjects. The allele frequencies in the HIV-infected and healthy populations were f(SD1 3' A) = 57.1%, f(SDF1) = 42.8%, f(SDF1 3' A) = 26.8%, and f(SDF1) = 73.1%, respectively. The allelic and genotypic frequencies of the SDF1 3' A in our population show significantly higher distribution profiles compared with those observed in other Caucasian, European, and African American populations. Our results were examined by chi(2) test and appear to confirm an association between polymorphism and AIDS progression. A higher odds ratio (>1) was found for the SDF1-3' A allele than for the wild-type allele (<1). Conclusion: This result seems to confirm that the SDF1-3' A allele is associated with acceleration and progression from HIV infection to AIDS in the Tunisian population.