Introduction: Rheumatoid arthritis (RA) is a crippling disease with a global prevalence of approximately 0.5%-1% in adults. Genetic, environmental and immunologic factors contribute importantly to pathogenesis of RA. American College of Rheumatology (ACR) assists in early diagnosis of the disease.
Aim: The aim of this study was to investigate the effects of HLA-DRB1 gene and anti-Cyclic Citrullinated Peptide (CCP) antibody on Clinical Disease Activity Index (CDAI) and to determine the frequency of HLA-DRB1 alleles in the patients with RA.
Materials and methods: In this descriptive-analytical study, 64 patients with RA referring rheumatology clinic of Hajar Hospital, Shahr-e-Kord, Iran were enrolled based on ACR criteria (1987) by convenience sampling. All patients were examined to assess primary CDAI and referred to laboratory for serologic tests [Rheumatoid Factor (RF) and anti-CCP]. After the patients' DNA was extracted, HLA-DRB1 was determined per single specific primer-polymerase chain reaction by inno-train kits. The patients were re-examined six months later.
Results: The most prevalent type of HLA-DRB1 in the studied patients was 04. In patients with HLA-DRB1 (04), HLA-DRB1 (01), and HLA-DRB1 (15), CDAI decreased pronouncedly after six months, but in other patients it did not (p<0.05). Of the patients, 81.3% had high titers of anti-CCP, but no association between anti-CCP and CDAI was found.
Conclusion: RA could be a multifactorial disease. The patients with HLA-DRB1 (04), HLA-DRB1 (01) and HLA-DRB1 (15) showed a good response to routine treatments. The patients with HLA-DRB1 (04) are likely to have no decrease in secondary CDAI. High titers of anti-CCP in patients may indicate the severity of RA in the studied region and perhaps environmental, genetic and unknown or idiopathic factors are aetiologically crucial.
Keywords: Human leukocyte antigen; Rheumatic diseases; Rheumatoid Factor.