The relationship with TIM-3 polymorphisms and asthma.

Recently, a new receptor named Tim-3 has been identified on Th1 cells. TIM-3 is a member of TIM gene family and affects immune response mediated by Th1. The ligand for Tim-3, galectin ?9, is expressed on T cells and interaction of Tim-3 with its ligand causes apoptosis in the Th1 cells. It has been shown that dysregulation of Tim-3 functions affects balance of Th1/Th2 immune responses. To support this view, correlations have been found between atopic diseases and polymorphisms of TIM-3 gene in various populations. In this study, we aimed to investigate whether any correlation exists between the occurrence of asthma and two of the TIM-3 gene polymorphisms, namely -574 T > G and +4259 G>T, in the Turkish population. For this purpose, we have isolated genomic DNA from peripheral blood of 76 asthmatic patients and 91 healthy individuals, and analysed for the presence of the above-mentioned polymorphisms using ARMS-PCR technique. For the -574 T > G polymorphism, we found that GG, GT and TT frequencies were 0.81, 0.17 and 0.01 in the control group and 0.75, 0.22 and 0.03 in the patient group, respectively (p=0.34, Odds ratio = 1,43). Whereas, for the +4259 G>T polymorphism, the genotype frequencies for TT, GT and GG were 0.79, 0.21, 0.0 for control group and 0.89, 0.11, 0.0 for the test group, respectively (p=0,13, Odds ratio = 0,540). We failed to detect a statistically significant difference with respect to the genotype frequencies of the patients and controls. Although, there was not a correlation between the presence of any of these polymorphisms and the occurrence of asthma, we have found that the genotype distribution of the Turkish population for the -574 T>G polymorphism exhibited a similar pattern to that of seen in Korean population. However, the distribution of the other polymorphism was found to be different from either Chinese or Korean populations. Key words: Asthma, Tim-3, Tim-3 4259 G>T, Tim-3 -574 T>G, ARMS-PCR