Association of ICOS and CD28 single nucleotide polymorphisms with pulmonary tuberculosis susceptibility

Objective To investigate the association of inducible co-stimulator (ICOS) and CD28 gene polymorphisms with pulmonary tuberculosis susceptibility. Methods In this case-control study, from Mar 2015 to Sep 2016, peripheral venous blood of 100 pulmonary tuberculosis patients (pulmonary tuberculosis group) in the Jintan People′s Hospital of Changzhou and 100 community physical examination volunteers (health control group) were collected. A total of 56 single nucleotide polymorphisms (SNP) in ICOS and CD28 sequences were selected and SNP genotype and allele frequency were analyzed using the next-generation sequencing technology. Association of these SNP with pulmonary tuberculosis susceptibility was investigated using linkage disequilibrium (LD) analysis and genetic models. Results Among these 56 SNP, 23 SNP with Hardy-Weinberg equilibrium P (HWE-P) value<0.001 or minimum allele frequency<0.05 were kicked out. The frequencies of T allele and TT genotype of ICOS gene SNP locus (rs55663036), and GG genotype of CD28 gene locus (rs45620941) in tuberculosis group were significantly higher than those in healthy control group (all P<0.05). There was a strong linkage imbalance between rs45620941 at CD28 locus and rs56262258 (r2=0.757). Conclusion The polymorphisms of rs55663036 of ICOS gene and rs45620941 of CD28 gene are significantly associated with the risk of pulmonary tuberculosis. Key words: Tuberculosis, pulmonary; Polymorphism, single nucleotide; Inducible co-stimulator; CD28