Immunoregulatory Role of Interleukin-37 in Rheumatoid Arthritis; Relation to Disease Activity and Joint Destruction

Abstract
Background: The Interleukin (IL)-37 is a member of IL-1 cytokines and reported to down-regulate inflammation as a natural suppressor of innate immune responses. We measured serum IL-37 concentration in Rheumatoid Arthritis (RA) patients and analyzed clinical disease activity and radio-graphic erosion in RA.
Aim of the Study: To throw some light on Interleukin-37 (IL-37) in patients with rheumatoid arthritis and its impact on disease activity and joint damage.
Subject and Methods: 30 patients diagnosed to had Rheu-matoid Arthritis (RA) selected from Outpatient Clinic of Physical Medicine, Rheumatology and Rehabilitation Depart-ment, Tanta University Hospitals fulfilling the American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) 2010 criteria for diagnosis of RA, and 20 apparently healthy individuals matched in age and sex participated as controls. Patients with other autoimmune diseases, acute coronary syndrome or any current infections were excluded. Disease Activity Score in 28 joints (DAS 28) was assessed for all patients; routine laboratory investigations (rheumatoid factor RF, anti-cyclic citrullinated peptide anti CCP, complete blood count CBC, Erythrocyte Sedimentation Rate ESR & C Reactive Protein CRP) and serum level of IL 37 measured by Enzyme-Linked Immunosorbent Assay ELISA were evaluated. Degree of joint destruction was assessed by Larsen score.
Results: Serum IL-37 level was significantly higher in RA patients than control and positively correlated with level of disease activity assessed by DAS-28 score, also with clinical and laboratory indicators of disease activity as well as degree of bone erosion measured by Larsen score.
Conclusion: IL-37 was increased in RA patients and its level was increased with disease activity, so it could prove to be potential biomarker for RA diagnosis, disease activity assessment and curative effect observation.