The influence of tumour necrosis factor α inhibitors treatment – etanercept on serum concentration of biomarkers of inflammation and cartilage turnover in psoriatic arthritis patients

Introduction
Effective treatment in psoriatic arthritis (PsA) patients can protect them from severe musculoskeletal complications. For appropriate monitoring of anti-tumour necrosis factor α (anti-TNF-α) treatment in PsA, specific biomarkers are needed.

Aim
To investigate whether biological treatment with anti-TNF-α (etanercept 50 mg once a week subcutaneously) affects the activity of selected mediators of inflammation and destruction of articular cartilage: interleukin-6 (IL-6), interleukin-18 (IL-18), matrix metalloproteinases 1 and 3 (MMP-1, MMP-3), cartilage oligomeric matrix protein (COMP), human cartilage glycoprotein (YKL-40) in serum of patients with PsA.

Material and methods
The study included 25 patients with PsA. The concentration of IL-6, IL-18, MMP-1, MMP-3, COMP and YKL-40 in serum was determined before, and 6 and 12 weeks after the beginning of anti-TNF-α treatment. Clinical severity of the disease according to the Body Surface Area, Psoriasis Area and Severity Index and Dermatology Life Quality Index as well as tender and swollen joint count (TJC, SJC) were also evaluated.

Results
The study disclosed a statistically significant reduction in the serum concentration of IL-6, MMP-1 and YKL-40 in PsA patients after 6 and 12 weeks from the beginning of anti-TNF-α treatment (p = 0.00018 for IL-6; p = 0.01242 for MMP-1; p = 0.03263 for YKL-40).

Conclusions
IL-6, MMP-1 and YKL-40 may be useful for monitoring the effectiveness of anti-TNF-α treatment