Abstract: LIU Li-jun, LU Jie, SUN Li-xin, HU Xiao-mei, YU Shu-ping, WANG Dan, LI Xue-fei, DUAN Xin-suo. Department of Dermatology, Affiliated Hospital of Chengde Medical College, Chengde 067000, Hebei, China Corresponding author: DUAN Xin-suo, Email: duanxinsuo2002@163.com 【Abstract】 Objective To investigate the possible mechanism involved in the therapeutic potential of polysaccharide nucleic acid fraction of bacillus Calmette-Guerin （BCG-PSN） for chronic urticaria. Methods Peripheral blood lymphocytes were obtained from 30 patients with chronic urticaria, and subjected to culture in vitro with the presence of various concentrations of BCG-PSN for 96 hours. Then, immunocytochemistry and enzyme-linked immunosorbent assay （ELISA） were performed to quantify the expression levels of interferon-γ （IFN-γ） and interleukin-4 （IL-4） on, and in the culture supernatant of, these cells. The peripheral blood lymphocytes from 30 health check-up examinees served as the control. Results The untreated lymphocytes from patients with chronic urticaria showed significantly lower IFN-γ expression （P < 0.05）, but significantly higher IL-4 expression （P < 0.05） compared with those from the controls. The 96-hour treatment with BCG-PSN induced an obvious increase in the level of IFN-γ, but a marked decrease in that of IL-4, in the culture supernatant of patient-derived lymphocytes, and with the increase in BCG-PSN concentration, the levels of both IFN-γ and IL-4 secreted by patient-derived lymphocytes gradually approximated to those by the control lymphocytes. Conclusion BCG-PSN may exert an immunomodulatory effect via upregulating the secretion of IFN-γ, but downregulating that of IL-4 by peripheral blood lymphocytes from patients with chronic urticaria.

Key words: BCG-PSN, IL-4