Abstract: Luan Chao, Yang Yonghong, Wang Yan, Liu Yi, Chen Min, Jiang Mingjun, Wang Baoxi. Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs; Hospital of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing 210042, China Corresponding author: Chen Min, Email: drchenmin@126.com 【Abstract】 Objective To investigate the role of tissue-resident memory T lymphocytes in the pathogenesis of psoriasis. Methods Clinical information was collected from 32 patients with progressive plaque psoriasis. Tissue specimens were obtained from both lesional and nonlesional psoriatic skin of all the patients, as well as from faded lesions in 9 of these patients. Tissue specimens from the normal skin of 10 healthy individuals served as the controls. Immunohistochemical staining was performed to detect the two characteristic surface markers CD69 and CD103 on tissue-resident memory T lymphocytes and to analyze the status of these T lymphocytes at different stages of psoriasis. The results of immunohistochemical staining were compared by t test. Results The mean number of CD69+CD103+ T lymphocytes per high-power field was significantly higher in lesional skin than in nonlesional skin of the 32 patients （11.34 ± 7.60 vs. 2.72 ± 4.20, t = 8.46, P < 0.01）, but similar between psoriatic lesions in the 9 patients before and after subsidence （14.33 ± 2.21 vs. 12.00 ± 4.58, t = 1.98, P = 0.08）. There was no significant difference in the mean number of CD69+CD103+ T lymphocytes between nonlesional psoriatic skin and normal control skin （2.72 ± 4.20 vs. 1.70 ± 2.98, t = 0.71, P > 0.05）. Conclusion Tissue-resident memory T lymphocytes may play a role in the formation and recurrence of psoriatic lesions in patients.

Key words: Psoriasis, Memory T lymphocyte, resident