When comparing the HLA-ABC allele groups frequencies between RA patients and HS, a statistically significant difference was observed for HLA-C*07 (OR = 2.29, p = 0.0015) and HLA-B*39.1 (OR = 1.88, p = 0.037) groups, in both cases being higher in RA patients (Table 1, Fig. 1). This evidence concerns the gene HLA-B and rheumatoid arthritis.