Programmed cell death 1 gene polymorphism association with activity and severity of systemic lupus erythematosus and rheumatoid arthritis in Egyptian patients

Abstract

Background Programmed cell death 1 (PD-1) is an inhibitory regulator molecule of T cells and B cells. The PD-1 gene polymorphism was reported to be associated with autoimmune diseases like systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), with conflicting results in different studies. Aim The aim was to investigate the potential association of PD-1.3 (rs11568821) polymorphism with SLE and RA in Egyptian patients and its relationship to the disease activity and severity. Patients and methods A total of 88 Egyptian patients with RA and 95 Egyptian patients with SLE as well as 85 healthy Egyptian controls were included in this study. PD1.3G/A (rs11568821) polymorphism was performed by restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR) technique. Results There was a significant difference in the distribution of A allele of PD-1.3 between RA, SLE, and control groups (38, 40, and 16%, respectively). Patients carrying A allele had high risk for RA and SLE in comparison with healthy control. Patients with RA with AA genotype had a significantly higher levels of C-reactive protein, erythrocyte sedimentation rate, anticyclic citrullinated peptide positivity, disease activity index 28, and modified Sharp score compared with those with GG and GA genotypes. Moreover, in SLE, AA genotype was significantly correlated with low C3 and C4, high proteinuria, positive anti-dsDNA antibody production, and damage index. Conclusion PD1.3G/A (rs11568821) polymorphism was associated with an increased risk of RA and SLE in Egyptian patients, so it could be a reasonable genetic risk factor for both diseases. Moreover, patients with RA and SLE who are homozygous for A allele are susceptible to have increased disease activity and severity.