Serum levels of IL-17, IL-4, and INFγ in Serbian patients with early rheumatoid arthritis

BACKGROUND Rheumatoid arthritis (RA) is a chronic, systemic, inflammatory disease with autoimmune etiology, characterized by synovial inflammation and destruction of joint cartilage and bone. There are controversial data about the profile of interleukin-17 (IL-17A), interleukin-4 (IL-4), and interferon-gamma (INFγ), indicating in some studies the key role of IL-17, while in others the Th1 cytokines. MATERIALS AND METHODS Serum samples of 31 early RA patients were evaluated for erythrocytes sedimentation rate (ESR), rheumatoid factor (RF), C-reactive protein (CRP), anti-cyclic citrullinated peptide antibodies (anti-CCP), and for the tested cytokines (IL-17A, IL-4, and INFγ). Disease activity score (DAS28) calculation was done for all patients. Control serum samples were obtained from 29 healthy volunteers. RESULTS The levels of tested cytokines were significantly higher (IL-17A, p < 0.001; INFγ, p < 0.001; IL-4, p < 0.01) in patients with early RA, compared to the healthy controls. In early RA patients, a strong correlation of serum IL-17A was found with DAS28, ESR, and CRP. Also, significant negative correlation was found between serum INFγ levels and the DAS28 score, indicating that INFγ may play a key role in maintaining immune homeostasis in patients with RA. CONCLUSION The mean serum IL-17A levels in patients with early RA, corresponded with the disease activity and severity. This might highlight the usefulness of the serum IL-17A level in defining the activity and predictive patterns, for aggressive disease therapy, and it might express specific therapeutically targets.