HLA-DR/DQ Genotypes in Kurd Patients with Rheumatoid Arthritis: Relation to Disease Activity

Specific alleles present at the HLA-DR/DQ loci seem to be associated with disease activity of rheumatoid arthritis.

In the present study, our aim was to investigate the distribution of HLA-DR/DQ alleles among Kurd patients with rheumatoid arthritis and to ascertain their relationship with disease activity.

Sixty five patients with rheumatoid arthritis (RA) and 65 apparently healthy subjects participated in the study. Diagnosis and disease activity were confirmed. Blood analyses, including those of laboratory markers of disease activity, were done. The 28 joint disease activity score (DAS-28) was calculated. HLA-DR/DQ typing was performed by polymerase chain reaction (PCR).The association between HLA-DR/DQ genotypes and disease activity was determined.

The most frequent alleles which were identified in RA patients were HLA-DRBI*01(23.1%) and HLA-DQBI*6(34.6%), whereas in healthy subjects, they were HLA-DRBI*11(17.7%) and HLA-DQBI*03(35.4%). Patients with active disease had high frequencies of HLA-DQBI*6 (40.0%) as compared to those with moderate disease activity (16.7%); OR=3.33. Patients with severe RA had increased frequencies of HLA-DQBI*6 (56.3%) as compared to those with mild RA (10.0%); OR = 11.57. Patients with positive rheumatoid factor (RF) and positive Anti-citrullinated peptide antibody (Anti-CCP), also had high frequencies of HLA-DQBI*06 (38.4% and 39.4%) as compared to frequencies of 11.1% and 15.4% which were seen in patients with negative rheumatoid factor and negative anti-CCP (OR= 4.98 and3.10) respectively.

HLA-DQBI*06 was found to be more common in Kurd patients and it was significantly associated with disease activity; this may indicate a high risk for developing a more progressive type of the disease.