Positive association between MIC gene polymorphism and tuberculosis in Chinese population.

The disease progression and morbidity of tuberculosis (TB) infections are determined by virulence of the micro-organism, host genetic factors and environmental factors. The highly polymorphic MHC class I chain-related gene (MIC) could serve as a potential host genetic candidate. To investigate the association of MIC polymorphism with TB infection, 124 patients and 191 ethnically matched controls from Hunan province, Southern China, were genotyped for the MIC polymorphism using polymerase chain reaction-sequence specific priming and sequencing-based typing. The results showed that allele frequencies of MIC-sequence and MICA-STR were different in TB patients in comparison to normal controls (both P < 0.05). MICA-A4 and MICA012:01 alleles were positive associated (OR = 2.42, 95% CI: 1.69-3.87; OR = 3.41, 95% CI: 2.19-5.33, respectively, both P < 0.05) while MICA -A5 were inversely associated (OR = 0.59, 95%CI: 0.41-0.94, P < 0.05) with TB. Homozygote MICA012:01/012:01 was observed to have significant risk effects on TB (OR = 4.76, 95% CI: 1.94-11.69, P0000-0001-5151-1853 < 0.05). Additionally, MICB*008 allele conduct a significant risk effect for TB (OR = 3.17, 95%CI: 1.80-5.61, P < 0.05). All the data showed that MIC polymorphism was associated with the variable susceptibility to TB in Chinese population.