Reduced levels of interleukin-37 in serum of patients with allergic rhinitis or asthma

Background. - Cytokines are suggested to play an important role in pathogenesis of allergic rhinitis (AR) and asthma (AS). Among these are members of the Interleukin (IL)-1 family that has been expanded to include 11 cytokines with pro -inflammatory and anti-inflammatory activities. The newly assigned member of this family, IL-37, has been recognized to exhibit a wide range of anti-inflammatory effects and its role in AR and AS pathogenesis has been proposed. Objectives. - This study explored serum levels of IL-37 in patients with AR and AS to assess its significance as a biomarker for both types of respiratory allergy. Methods. - A case-control study was conducted on 52 AR patients, 60 AS patients and 61 controls. IL-37 level was determined using enzyme-linked-immunosorbent-assay kit. Results. - Median level of IL-37 was significantly decreased in AR and AS patients (105.9 and 88.1 and pg/mL, respectively) compared to controls (180.2 pg/mL; P-value < 0.001). The lowest level was observed in the age group > 40 years of AR and AS patients, and in AR patients who were classified under disease duration < 5 years. AR and AS patients classified by gender, family history of allergy, symptoms, type of allergen and atopy showed no significant differences in the distributions of IL-37 levels. Receiver operating characteristic curve analysis revealed that IL-37 occupied a significant area under curve in AR and AS (0.781 and 0.897, respectively; P-value < 0.001). Conclusions. - IL-37 was down-regulated in serum of AR and AS patients, particularly in patients older than 40 years of age. 2021 Elsevier Masson SAS. All rights reserved.