Differential effects of t helper-17 cytokines on the functions of granulocytes isolated from schistosoma mansoni-infected patients and healthy individuals

Abstract

Background and aim The role of T helper-17 lymphocytes in the regulation of the immune response against Schistosoma soluble egg antigens is still controversial. In this study, the in-vitro effects of T helper-17 cytokines [interleukin (IL)-17 and IL-22] on granulocyte functions isolated from Schistosoma- infected patients or healthy individuals were examined. Patients and methods Twenty-seven Schistosoma mansoni- infected patients and 13 healthy individuals from Kasr Al-Aini Viral Hepatitis Center were enrolled in the present study. Granulocytes were isolated from whole blood of patients and controls by Ficoll–Paque density gradient for removal of the mononuclear layer and then lysis of red blood cells. Granulocytes were stimulated in vitro with soluble egg antigen in the presence of IL-17, IL-22, or both. After 24 h, the supernatants were collected for the measurement of tumor necrosis factor (TNF)-α, hydrogen peroxide (H 2 O 2 ), myeloperoxidase (MPO), and nitric oxide (NO) using enzyme-linked immunosorbent assay as surrogate markers for granulocyte functions. Results The results indicated that the presence of IL-17 significantly decreased ( P 2 O 2 , MPO, and NO production by granulocytes isolated from Schistosoma- infected patients. In contrast, in the presence of IL-22 or both IL-17 and IL-22, there were significant increases in the production of H 2 O 2 and TNF-α by granulocytes isolated from Schistosoma- infected patients. Moreover, in the presence of both IL-17 and IL-22, nonsignificant changes were observed in MPO or NO levels compared with those in the control participants. Conclusion IL-17, in contrast to IL-22, inhibited the functional activity of granulocytes isolated from S. mansoni- infected patients. Therefore, neutralization of IL-17 may work as a therapeutic strategy for these patients.