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.