Association of common T cell activation gene polymorphisms with multiple sclerosis in Australian patients.

Susceptibility to multiple sclerosis (MS) may be influenced by the interaction of several genes within a biological pathway. T cell activation and costimulation may be potentially important in MS pathogenesis. We have therefore investigated associations between MS and polymorphisms in the CD152 (CTLA-4), CD28, CD80 and CD86 genes in Australian patients. We found no significant MS association with CTLA-4 exon 1 +49 alleles, and meta-analysis showed no significant association across nine comparable datasets (OR=1.04, p=0.54), nor with primary progressive MS across seven datasets (OR=1.19, p=0.21). Haplotype analysis showed a trend towards a decrease of the CTLA-4-1722C, -1577G, +49G haplotype in +49 G positive MS patients compared with controls (p=0.06). Screening of CD28, CD80 and CD86 genes identified novel polymorphisms in the putative promoter regions of CD28 (-372 G/A) and CD86 (exon 2 -359 deletionAAG). There was a significant increase of the CD28 -372 G allele frequency in MS patients vs. controls (p=0.045) and a trend towards a significant interaction between this allele and the CTLA-4 +49 G allele (OR=4.00, p=0.058). Our results suggest that the CTLA-4 +49 alone is not associated with overall susceptibility to MS, but may be important in clinical subsets of patients and/or may interact epistatically with other gene polymorphisms.