Effects of the polysaccharide nucleic acid fraction of bacillus Calmette-Guérin on the production of interleukin-2 and interleukin-10 in the peripheral blood lymphocytes of patients with chronic idiopathic urticaria

Abstract

Urticaria is one of the most frequent dermatoses and its prevalence in the general population is estimated to be ~20%, whereas a substantial percentage of the cases may be classified as chronic idiopathic urticaria (CIU). The inflammatory response presenting with spontaneous wheals exhibits pro-inflammatory characteristics, involving a prominent role for lymphocytes with a mixed Th1/Th2 response in which interleukin (IL)-2 and IL-10 are prominently secreted by Th1 and Th2 cells, respectively. In CIU patients, it was demonstrated that IL-10 production was elevated and IL-2 reduced compared to controls. Therefore, inhibition of IL-10 and promotion of IL-2 production by the lymphocytes, indicating Th2 inhibition and Th1 promotion, may facilitate the treatment of CIU. Whether the polysaccharide nucleic acid fraction of bacillus Calmette-Guérin (BCG-PSN), which possesses multiple immunomodulatory properties, has that potential, remains to be elucidated. In this study, BCG-PSN was used on lymphocytes isolated from CIU patients, with healthy donors used as controls. Immunocytochemistry and ELISA were used to detect IL-2 and IL-10 production. It was demonstrated that the IL-2 production by the lymphocytes in the CIU group was significantly lower compared to that in the healthy control group and it increased sequentially with the increase of the concentration of BCG-PSN used. By contrast, the IL-10 production by the lymphocytes in the CIU group was significantly higher compared to that in the healthy control group and decreased sequentially with the increase of the concentration of BCG-PSN used. Thus, it may be concluded that the BCG-PSN has the potential to promote IL-2 and inhibit IL-10 production in the lymphocytes of CIU patients, facilitating the treatment of CIU.