HLA-B*58 and HLA-C*2 Alleles Are Associated with the Occurrence of Rheumatoid Arthritis Among Omanis

Background/Objectives: Rheumatoid arthritis (RA) is an autoimmune disease that is influenced by polymorphisms in the HLA molecules. Only a few studies assessed the presence of an association between HLA class I genes and RA. Moreover, ethnic background influences the association of HLA molecules and RA. HLA-I molecules are essential for the activation of CD8 T cells and natural killer (NK) cells. The implication of these cells in RA pathogenesis is controversial. Therefore, we investigated the presence of associations between HLA-I alleles and RA in Omani patients. Methods: HLA class I alleles were genotyped in a total of 206 volunteers (102 RA patients and 104 controls). The control group included volunteers who were not affected by any known disease. The Chi square test was used to investigate the significance of the associations between the HLA alleles and the occurrence of RA. A corrected p value (p_c) was calculated using the Bonferroni correction. Results: The frequency of HLA-B*58 was ≈2.7-fold lower in RA patients (10.8%) compared to the control group (28.8%; p_c = 0.0324). Moreover, the frequency of HLA-C*02 in RA patient was ≈8-fold higher compared to the control group (p_c = 0.0104). Conclusions: This study is the first to demonstrate the presence of association between HLA-B*58 and HLA-C*02 and the occurrence of RA, which could guide future research on targeted therapies. It also suggests that these HLA alleles might influence CD8 T cells and NK cells implication in RA pathogenesis.