Serum levels of IL-17A increase in Asthma but not in accordance with Serum level of IgE and Asthma Severity

Background and Aims: Recent evidence suggests that T helper (Th) 17 cells are involved in the emergence of asthma. Th17 cells have a key role in inducing inflammation in asthmatic airways thus Interleukin (IL)-17A, the main cytokine of Th17, contributes to airways inflammation. Materials and Methods: We evaluated the level of IL-17A and total immunoglobulin E (IgE) in sera of 100 asthmatic patients and 81 healthy controls by ELISA to determine how serum concentration of IL-17A is associated with asthma severity. We classified patients into three groups mild (n=28), moderate (n=33) and severe cases (n=39). Results: Respectively, serum IL-17A and IgE concentrations were significantly higher in the asthmatic patients than the control group (p=0.026 and p<0.01). Mean of serum IL-17A and IgE values were 37.73 pg/ml and 39.02 IU/ml in the control group and 68.55 pg/ml and 295.87 IU/ml in the patients group. Nevertheless there were non-significant differences between the three groups of asthmatic patients. Respectively, mean of serum IL-17A and IgE values were 94.17 pg/ml and 255.07 IU/ml in the mild group, 71.29 pg/ml and 271.27 IU/ml in the moderate group, and 47.85 pg/ml and 345.97 IU/ml in the severe group. Moreover, there was no correlation between serum levels of IL-17A and IgE. Conclusions: In this study we found that IL-17A, like IgE, rises in sera of asthmatic patients though in a different manner. IgE increases in serum consistent with disease severity though the increases of IL-17A in serum has an inverse relationship with IgE rising.