HLA class II, MICA and PRL gene polymorphisms: the common contribution to the systemic lupus erythematosus development in Czech population

The genetic components contribute to the systemic lupus erythematosus development. This study for the first time determined the distribution of the polymorphisms and linkage disequilibrium in HLA class II, MICA and PRL gene among patients suffering from SLE and healthy Czech individuals. DNA was obtained from the peripheral blood cells of 123 SLE patients and 96 healthy people. Allele variants of the HLA class II, MICA transmembrane polymorphism and PRL extrapituitary promoter −1149G/T SNP were detected using the sequence-specific primers analysis, PCR-fragment analysis and PCR–RFLP, respectively. In Czech population, only DRB1*03-DQB1*0201 haplotype is significantly associated with increased risk for SLE development: the frequency in SLE group was 44.7% in comparison with 15.2% in controls, P _c < 0.0001; OR 4.54 CI 95% (2.36–9.09). The MICA-A5.1 allele is present significantly more often in SLE (55.7%) than controls (39.9%), P _c = 0.005; OR 1.88 CI 95% (1.29–2.77), and the combination of HLA DRB1 *03 together with MICA-A5.1 is strongly associated with SLE [P _c < 0.000001; OR 9.71 CI 95% (3.4–27.7)]. On the other hand, the MICA-A6 allele is less frequent in SLE patients compared to controls, 10.6% and 19.7%, respectively [P _c = 0.035; OR 0.48 CI 95% (0.28–0.82)], and the combination of absence both alleles MICA-A6 and HLA DRB*11 seems to be risk for SLE development compared to controls, 84.6 and 70.2%, respectively, [P _c = 0.0003 OR 2.32 CI 95% (1.47–3.70)]. We found that only G allele of the −1149 G/T SNP is associated with specific clinical manifestation of SLE, arthritis [P _c = 0.022; OR 2.63, CI 95% (1.45–4.81)]. HLA class II-MICA combinations may increase/decrease a risk for SLE development. Multiple studies focusing on the ethnical differences as well as genetic-epigenetic relationships are necessary for better understanding SLE pathogenesis.