HLA-DRB1 alleles in Egyptian rheumatoid arthritis patients: Relations to anti-cyclic citrullinated peptide antibodies, disease activity and severity

BackgroundHuman leukocyte antigen HLA-DRB1 alleles encoding a common amino acid sequence called shared epitope in the third hypervariable region of DRB1 molecule have been identified as risk alleles for rheumatoid arthritis (RA).Aim of the workThe aim was to study HLA-DRB1 01, 04 and 10 alleles in Egyptian RA patients and determine their relation with anticyclic citrullinated peptide (anti-CCP) antibody level, disease activity, clinical and radiological severity.Patients and methodsThe study involved 40 RA patients and 20 control. Simplified disease activity index (SDAI) was calculated, clinical severity was assessed using the mechanical joint score (MJS) and radiological severity evaluated using the simple erosion narrowing score (SENS). HLA-DRB1 genotyping and anti-CCP antibodies were detected.ResultsThe mean patients' age was 41.6 ± 12.7 years and disease duration 8.9 ± 7.7 years. The frequency of HLA DRB1 01, 04 and 10 in patients was 42.5%, 60% and 25% respectively. Of them 04 was significantly higher than in controls (p = 0.013) and was associated with anti-CCP positive cases (p = 0.0008) while the absence of HLA-DRB1 alleles was significantly associated with negative anti-CCP negative RA (p = 0.0008). There were significant associations between HLA-DRB1 01 and 04 with SDAI (p = 0.0002 and p = 0.005, respectively); between HLA-DRB1 04 and 10 with SENS (p = 0.002 and p = 0.001 respectively) and between HLA-DRB1 01, 04 and 10 with MJS (p = 0.02, p = 0.03 and p = 0.02, respectively).ConclusionHLA-DRB1 04 is associated with RA in Egyptian patients and is strongly associated in the production of elevated titers of anti-CCP antibodies which contribute to the development, severity and activity of the disease.