Association study of MICA-TM and HLA-class I polymorphism with uveitis in South Tunisian population

Background

Uveitis refers to intraocular inflammation. The pattern of uveitis is largely influenced by a multitude of factors including genetic background.

Aim

The purpose of our study was to identify the association between the polymorphism of the transmembrane region of MICA (MICA-TM) and uveitis in Tunisian patients with intraocular inflammation.

Patients and methods

A total of 79 Tunisian patients and 123 healthy controls were enrolled in our study. HLA-class I phenotyping was performed by microlymphocytotoxicity complement dependent and MICA-TM was genotyped by a semiautomatic fluorescent-labelled PCR method, amplicons were analysed on ABI Prism 310 genotyper. Comparisons of allele frequencies between patients and controls, and between patients’ subgroups were performed using SPSS 20.0.

Results

In our 79 patients, HLA-B27 showed a significant increased frequency when compared with healthy controls (P = 0.003, 7.88 [95% IC = 2.17–28.65]). The association was more significant when considering idiopathic anterior uveitis (P = 0.00002, OR = 11.65 [95% IC = 3.06–45.17]). No MICA allele was significantly increased in uveitis groups compared to controls. In the idiopathic uveitis group, MICA-A4 was associated with late age of onset of disease (P = 0.04). HLA-B51 and MICA-A6 were associated respectively with severe tyndall (P = 0.008) and with the presence of synechiae (P = 0.007).

Conclusion

Some clinical features of uveitis may be influenced by specific MICA-TM alleles. In our South Tunisian population, MICA plays a disease modifying role, rather than being an important gene in the susceptibility for developing of uveitis.