Quantitative analysis of elastase and cathepsin G mRNA levels in peripheral blood CD14+ cells from patients with rheumatoid arthritis

• We assessed mRNA levels of ELANE and CTSG in peripheral blood CD14+ cells from RA patients.
• ELANE expression is up regulated at the transcript level in CD14+ cells from RA patients.
• Expression levels of ELANE and CTSG correlate positively.
• High levels of ELANE correlate positively with RA activity determined by patients.

In rheumatoid arthritis (RA) activity of serine proteases is an important factor contributing to destructive changes in the joints. The aim of this study was to compare elastase (ELANE) and cathepsin G (CTSG) mRNA levels in peripheral blood CD14+ cells obtained from RA patients, healthy subjects (HS) and patients with osteoarthritis (OA). CD14+ cells were isolated from peripheral blood by positive magnetic selection. The expression levels of ELANE and CTSG were determined by quantitative real-time PCR. ELANE mRNA expression was significantly higher in RA patients when compared to HS (p < 0.001) and OA patients (p < 0.001). The results suggest that in RA, peripheral blood CD14+ cells express serine protease mRNA as a result of systemic mechanisms probably related to inflammation/cytokines before entering inflamed joints.