Rheumatoid arthritis (RA) is a common, complex autoimmune disease known to be associated with inheritance of certain human leukocyte antigen (HLA)-DR alleles in different populations. This study investigated the association of DRB1 alleles in Kuwaiti patients with RA.
DRB1 alleles were analyzed in 47 Kuwaiti patients and 70 ethnically matched controls using a DNA-based sequence specific primer (SSP) method.
The frequency of DRB1*04 allele was higher in patients compared to the controls (P < 0.012). The association with of HLA-DRB1*04 allele in our patients with RA was accounted for mainly by the seropositive group of patients (P < 0.05). Moreover, five patients were homozygous for DRB1*4 compared to none in the controls. None of the other DRB1 alleles tested was significantly higher in the patients. All patients homozygous for the DRB1*04 allele were females. There was no statistically significant difference in the frequency of DRB1*04 allele in patients classified according to presence of erosive disease or extra-articular manifestations.
Our results indicate that in Kuwaiti patients, RA is associated with the presence of DRB1*04 allele. The lack of association with severity or the phenotype of RA is not surprising since this is a hospital-based study where patients tend to have a more severe disease.