Interleukin-6 and soluble interleukin-2-receptor in psoriatic arthritis: Correlations with clinical and laboratory parameters

Objective. In this study, we evaluated the relationships of IL-6 and sIL-2R levels with the main clinical and laboratory parameters in PsA patients with peripheral polyarthritis. Methods. Serum levels of IL-6 and sIL-2R were measured by an enzyme immunoassay kit in patients with peripheral (< 4 joints) PsA (n=47), with RA (n=41), or with psoriasis (n=15) and in healthy volunteers (n=15). Results. The patients with PsA had higher serum levels of IL-6 and sIL-2R than healthy volunteers and psoriatic patients, while they showed lower levels of IL-6 and sIL-2R than RA patients. We found abnormal values for IL-6 and sIL-2R in 63.8% and 57.4% of PsA patients, respectively. IL-6 levels correlated with the number of painful and swollen joints, RAI, physician's assessment, CRP and ESR, while sIL-2R levels correlated only with the number of swollen joints, the physician's assessment and ESR. IL-6 and sIL-2R correlated with each other. Conclusion. Our study shows that IL-6 and sIL-2R may play a role in the pathogenetic mechanism of psoriatic arthritis.