Rheumatoid arthritis (RA) is a systemic autoimmune disease affecting up to 1% of the population worldwide. The aim of the present study was to investigate whether miRNA-146a rs2910164, miRNA-499 rs3746444, IRAK1 rs3027898 and PADI4 rs1748033 polymorphisms are associated with susceptibility to RA in Egyptians and whether they influence disease severity and activity.
The study was performed on 104 unrelated RA patients and 112 healthy subjects. RA patients were further subdivided into active and inactive RA groups. Polymorphisms were genotyped by using real-time polymerase chain reaction with TaqMan allelic discrimination assay.
Significant differences in the frequency of miRNA-146a rs2910164, miRNA-499 rs3746444, IRAK1 rs3027898 and PADI4 rs1748033 alleles and genotypes were observed between RA patients and controls. Only CA and AA genotypes of IRAK1 rs3027898 shows a significant difference between active and inactive subgroups. MiRNA-146a rs2910164 and IRAK1 rs3027898 polymorphisms were a risk factor for predisposition to RA in codominant and dominant tested inheritance models, while, the miRNA-499 rs3746444 and PADI4 rs1748033 polymorphisms were a risk factor in codominant and recessive one. CG and GG genotypes of miRNA-146a rs2910164 were associated with positive erosions. CA genotype of IRAK1 rs3027898 was associated with low disease activity and negative erosions, while, the AA genotype was associated with high disease activity. CC genotype of PADI4 rs1748033 was associated with negative rheumatoid factor.
The 4 studied SNPs were likely to play an important role in the susceptibility to RA and can influence disease severity and activity in Egyptian population.