Association between the HLA-DRB1 with the disease activity parameters among Egyptian RA patients

Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (ACCP), key markers of seropositivity in rheumatoid arthritis (RA), have been linked to the HLA-DRB1 allele. This study aimed to determine the prevalence of HLA-DRB1 in RA patients in tertiary hospitals and assess its association with disease severity. A total of 47 patients diagnosed according to the 2010 EULAR/ACR criteria were enrolled in this cross-sectional study. Participants underwent comprehensive clinical assessments, laboratory investigations—including RF, ACCP, CRP, ESR, liver enzymes, and HLA-DRB1 genotyping via PCR—and were evaluated using the DAS28-CRP score. Results showed that patients positive for HLA-DRB1 had significantly higher DAS28-CRP scores, elevated CRP, RF, and ACCP levels, and increased counts of swollen and tender joints compared to HLA-DRB1-negative individuals. Despite these findings, there was no statistically significant difference in disease activity classification between the two groups. Univariate logistic regression revealed a strong association between disease severity and elevated inflammatory markers. Multivariate analysis identified CRP >6 mg/L as the most significant independent predictor of moderate to severe disease (OR = 144.000, 95% CI: 11.589–178.248, P = 0.001). In conclusion, the presence of HLA-DRB1 is associated with more severe RA, reflected by higher inflammatory markers and joint involvement. However, no association was observed between HLA-DRB1 and extra-articular manifestations or comorbid conditions.