Abstract: He Yanni, Zhao Ying, Zeng Yibin, Zhang Tong, Du Lingbo, Zhu Ruizheng, Wang Wuqing Department of Dermatology, Central Hospital of Minhang District, Shanghai 201199, China （He YN, Zeng YB, Zhang T, Du LB, Zhu RZ, Wang WQ）; Department of Dermatology, Huashan Hospital, Fudan University, Shanghai 200040, China （Zhao Y） Corresponding author: Wang Wuqing, Email: wuqingw2006@sina.com 【Abstract】 Objective To determine the frequency of Th22 cells and of their related cytokines in peripheral blood of patients with alopecia areata （AA）, to investigate their significance, and to explore the role of T lymphocytes in the occurrence of AA. Methods A total of 38 patients with AA were enrolled from Central Hospital of Minhang District in Shanghai between January 2015 and May 2016, and served as the case group. At the same time, 38 healthy people served as the control group. Peripheral blood samples were obtained from these patients and controls. Flow cytometry was performed to determine the percentage of Th22 cells, and enzyme-linked immunosorbent assay （ELISA） to measure serum levels of interleukin-22 （IL-22） and IL-17. Results Compared with the control group, the case group showed significantly increased percentages of Th22 cells, Th17 cells, IL-17+IL-22+CD4+ T cells and IFN-γ+IL-22+CD4+ T cells （all P < 0.01）, as well as serum levels of IL-22 and IL-17 （both P < 0.05）. A significant increase was observed in percentages of Th22 cells, Th17 cells, IL-17+IL-22+CD4+ T cells and IFN-γ+IL-22+CD4+ T cells, as well as serum levels of IL-22 and IL-17, in patients with severe AA compared with those with mild AA, and in patients with active AA compared with those with stable AA （all P < 0.05）. Conclusion Th22 cells and their related cytokines may participate in the occurrence, development and prognosis of AA.