Serum levels of IL-10, IL-17F, and IL-33 in asthmatic patients of south India

Background: Asthma is an inflammatory disorder of the airways in which the development of inflammation involves an intricate network of cytokines. Objectives: This study was aimed to compare serum levels of IL-10, IL-17F and IL-33 in asthmatic patients and non-asthmatic controls and correlate with asthma severity and various demographic, clinical, spirometric and laboratory variables. Methods: Asthmatics were diagnosed and classified as mild, moderate and severe persistent asthma according to GINA guidelines. Age and gender-matched healthy controls were selected from the general population. Using ELISA (enzyme linked immunosorbent assay) method, serum levels of IL-10, IL-17F, and IL-33 were evaluated in 44 asthmatics and 44 non-asthmatic controls. Results: This is one of the first reports showing a significant difference in serum levels of three important cytokines associated with asthma, anti-inflammatory IL-10 and pro-inflammatory IL-17F and IL-33 in the same subset of asthmatic patients. Our results showed diminished level of IL-10 and elevated levels of IL-17F and IL-33 in asthmatics than in controls (p < 0.001). No correlation was observed with most of the demographic, clinical and laboratory variables for the levels of all the three cytokines. IL-17F was associated negatively to FVC% predicted (Forced Vital Capacity) and positively to number of allergens sensitized and FEV1 (Forced Expiratory Volume in one second) reversibility. Conclusion: The association between IL-17F and asthmatic phenotypes such as asthmatics with reduced FVC, higher degree of sensitization and post bronchodilator reversibility needs further evaluation