In our group, the association of the HLA-DRB1*04 allele and the DRB1*04:04 genotype with the development of RA are in concordance with the abovementioned studies, whereas the data obtained on the HLA-DRB1*01 alleles and the HLA-DRB1*01*16 genotype were different, which could be explained by the population characteristics. Here, HLA-DRB1 is linked to rheumatoid arthritis.