An Elevated <em>IL10</em> mRNA Combined with Lower <em>TNFA</em> mRNA Level in Active Rheumatoid Arthritis Peripheral Blood

Abstract

We aimed to investigate the expression of pro-inflammatory cytokine genes TNFA, IL6, IL12B, IL23, IL18 and immunoregulatory genes FOXP3, TGFB1, and IL10 in the peripheral blood of patients with rheumatoid arthritis (RA) at messenger ribonucleic acid (mRNA) level. The total RNA was isolated from peripheral blood samples. Real-time quantitative PCR was used to perform TaqMan-based assays to quantify mRNAs from 8 target genes. IL23A was upregulated (1.7-fold), whereas IL6 (5-fold), FOXP3 (4-fold), and IL12B (2.56-fold) were downregulated in patients compared to controls. In addition, we found a strong positive correlation between the expression of FOXP3 and TNFA and a moderate correlation between FOXP3 and TGFB1. These data showed the imbalance of the T helper (Th) 1/Th17/ T regulatory (Treg) axis at a systemic level in RA. In cases with active disease, the IL10 gene expression was approximately 2-fold higher; in contrast, the expression of FOXP3 was significantly decreased (3.38-fold). The main part of patients with higher disease activity expressed upregulation of IL10 and downregulation of TNFA. Different disease activity cohorts could be separated based on IL10, TNFA and IL12B expression combinations. In conclusion, our results showed that active disease is associated with an elevated IL10 and lower TNFA mRNA level in peripheral blood cells of RA patients.

Keywords

• blood cells
• cytokines
• disease activity
• FOXP3
• mRNA
• rheumatoid arthritis