Functional MICA-129 polymorphism and serum levels of soluble MICA are correlated with ulcerative colitis in Chinese patients

Background and Aim: The aim of the present study was to evaluate the contribution of the dimorphism (MICA‐129 val and met) to the genetic susceptibility and functions of ulcerative colitis (UC) in patients in central China. Methods: Genotyping of MICA‐129 was performed in 272 consecutive UC patients and 560 age‐ and sex‐matched healthy individuals by using a polymerase chain reaction‐sequencing based typing (PCR‐SBT) method. A total of 93 patients and 98 healthy individuals serum soluble MICA (sMICA) concentrations were detected by enzyme‐linked immunosorbent assay. Results: Both the frequencies of the variant allele (val) and genotype (val/val) in the MICA‐129 gene were significantly higher in UC patients than in the controls (77.4% vs 71.7%, P = 0.015, 95% confidence interval [CI]: 1.064–1.716; 56.9% vs 46.4%, P = 0.005, 95% CI: 1.142–2.047). Serum sMICA levels were significantly higher in UC patients than in the controls (560 ± 140 pg/mL vs 157 ± 67 pg/mL, P < 0.0001). The genotype also affected the extent and the activity of UC. Furthermore, patients with the MICA‐129 val/val genotype had higher serum sMICA levels than those with the val/met + met/met genotype (661 ± 352 SD pg/mL vs 523 ± 245 SD pg/mL, 95% CI: 13.47–265.35, P = 0.03). In addition, patients with severe colitis were more susceptible to higher levels of sMICA than those with mild colitis. Conclusions: Our findings showed that the MICA‐129 gene polymorphism as a functionally relevant gene was associated with UC and seems to play a potential role in the development of UC in patients in central China.