Abstract: Objective To explore the changes in Thl7 cell counts and serum IL-17A levels in HIV/HCV co-infected patients. Methods Thirty HIV/HCV co-infected patients,30 HIV infected patients,30 HCV infected patients and 30 healthy subjects were selected in this study. The percentage of CD4⁺T cells and Th17 cells in peripheral blood,and IL-17A in sera were detected by FCM and ELISA,respectively. Results The percentage of CD4⁺T cells in HIV and HIV/HCV co-infected patients were （310.23±114.35）/μl and（218.42±112.47）/μl,respectively,both were significantly lower than that in the healthy controls[（735.46±121.52）/μl,P<0.05],while the percentage of CD4⁺T cells in HIV/HCV co-infected group was even lower than in HIV infected patients（P<0.05）; There was no significant difference in CD4⁺T cells between HCV infected patients[（719.47±123.72）/μl] and the controls;The percentage of Th17 and serum level of IL-17A in HIV infected patients were（2.48±0.90）% and （25.18±12.63）pg/ml,significantly lower than those in the controls [（3.95±1.23）% and（39.15±16.30）pg/ml,P<0.05];The percentage of Th17 and serum level of IL-17A in HCV infected patients were（5.48±0.90）% and（45.24±15.72）pg/ml,significantly higher than those in the controls（P<0.05）;The percentage of Th17 and serum level of IL-17A in HIV/HCV co-infected patients were（1.76±0.42）% and（16.49±7.54） pg/ml,both significantly lower than those in HIV infected patients[（2.48±0.90）% and （25.18±12.63）pg/mL,P<0.05]. Conclusions Co-infection of HCV may influence the immune response in HIV infected patients,which might lead to the involvement of Th17 and IL-17A cytokine.

Key words: Hepatitis C, Human immunodeficiency virus, T lymphocytes, T helper cell 17, Interleukin 17A