Search

The association between multiple sclerosis (MS) and tumor necrosis factor-alpha gene (TNF-α) polymorphisms has been analyzed in several studies, but conflicting results have been reported. The main purpose of this study was to integrate previous findings and explore whether the three single nucleotide polymorphisms (SNPs; -238G/A, -308G/A, and -376G/A) of TNF-α are associated with susceptibility to MS. A total of 2,639 patients and 3,303 controls from 21 studies, which were identified by searching the ISI Web of Knowledge database and the PubMed database up to December 2009, were collected for this meta-analysis. The association between MS and TNF-α -238G/A, -308G/A, and -376G/A was previously analyzed in 4, 18, and 4 studies, respectively. Overall, no associations were identified for the TNF-α -238G/A polymorphism and MS in any of genetic model. Similarly, no associations were found for the TNF-α -308G/A polymorphism and MS or between the TNF-α -376G/A polymorphism and MS. Furthermore, no significant association between the three SNPs and MS was identified using subgroup analyses examining ethnicity and clinical manifestation. The results of the present study indicated that TNF-α -238G/A, -308G/A, or -376G/A may not be the main risk factor for MS, which should be interpret with caution for the limited study numbers.

It has been reported that single nucleotide polymorphisms (SNPs) in the promoter of the CCR5 gene are associated with the risk for HIV-1 infection and AIDS progression. Using resequencing, we performed a systematic survey of 78 HIV-1 seropositive individuals and 70 population-matched healthy control individuals from northern China to investigate SNPs of the CCR5 gene promoter and evaluated their effects on HIV-1 infection and the progression of AIDS. Linkage disequilibrium (LD) plots and haplotypes were generated using Haploview software. The association analyses were statistically compared using the Chi-square test with SPSS13.0 software for Windows. Seven SNPs (58755A>G, 58791C>T, 58934G>T, 59029A>G, 59353C>T, 59402A>G and 59653C>T) in the region of the CCR5 gene promoter were evaluated in this study. Among the seven SNPs, the minor allele frequencies of 58755G and 58791T were less than 2%. The differences in frequencies of the other five SNPs were not significant between case and control cohorts (P>0.05). In the case cohort, the association between these SNPs and clinical features (CD4+ T-lymphocyte counts and clinical categories) was not significant (P>0.05); however, there was a significant association between the haplotype GGTAC and susceptibility to HIV-1 infection (P<0.05), which is not consistent with other reports studied in different populations. The results suggest that the haplotype GGTAC may have a role in the process of HIV-1 infection in the northern Chinese population.