Study Of The Relativity Between Chronic Idiopathic Urticaria And Leptin

Chronic idiopathic urticaria(CIU)is a kind of refractory and incurable skin disease,accounting for about 50% of chronic urticaria. Currently, authors believed that the pathogenesis of CIU might be related with immunologic mechanism. And it was reported that there were about 30% of CIU whose pathogenesis might have the relationship with autologous Ig-G antibody, which suggested the participation of auto-immunologic mechanism, also called autoimmunity urticaria. However, the pathogenesis of not-autoimmunity urticaria was mostly mediated by I type allergy. Recently, the unbalance theory of Th1-Th2 had been paid more attention in some allergic diseases. Chronic urticaria is belonged to Th2 type. The accentuation of Th2 cells could accelerate the synthesis of IgE,in addition, the cytokines such as interleukin 4 (IL-4) and IL-10 produced by the cells also could promote mast cells to release histamine.Leptin is a polypeptide hormone,regulating immune and endocrinic functions of organisms. Studies showed leptin induced Th1 type immunoreaction, moreover, reacted with diverse cytokines and immunocytes. Therefore, the relationship between leptin with immunologic diseases had become the focus. It was reported that many immune skin diseases were related with leptin, but now few study was reported about the relationship between leptin and chronic urticaria. For this reason, our present study was aimed at evaluating the level of leptin between CIU patients and normal persons, and analysing roles of leptin in the morbility of CIU.In this study, 45 patients of CIU and 32 healthy voluntaris were included from Jan,2006 to Jun,2006 in Second Hospital of Jilin University. Autologous Serum Skin Test (ASST) was used and CIU patients were divided into ASST positive group and ASST negative group according the results from the test. In the meantime, to the 45 patients of CIU, the assay kit of serum allergen specific IgE antibody was selected to detect serum IgE antibody from food andrespiration and according to the results, they were divided into IgE positive group and IgE negative group.The level of serum leptin was detected by radioimmunoassay in CIU group and healthy control group that matched each other in age, gender and BMI. According to Foxpro data base, there were following results and conclusion: (1) The leptin level of female CIU patients was nearly two times higher than healthy female voluntaris, the significant difference might be related with sex hormone. (2) The positive rate of ASST was 31.7%. It indicated that functionality circulating histamine releasing factors might play a role in some CIU patients'serum. ASST could be used as a test to screen autoimmunity urticaria. (3) The total positive rate of IgE is 42.22%, of which the positive rate of aspiration allergen and ingestion allergen was respectively 28.89% and 33.33%. It meant in vitro detection of IgE might be significant in etiological diagnosis of CIU. The total positive rate of IgE of ASST positive group was higher than that of ASST negative group, suggesting the morbility ASST negative group might be related with serum IgE, and in the meantime, confimed the relationship between not- autoimmunity urticaria and I type allergy mediated by IgE. (4) The leptin level of CIU group was lower than that of control group. It suggested that leptin might play an important role in the advancement of CIU as an immunoregulation factor. (5) Neither positive or negative ASST group's leptin level was higher than control group (P=0.002, P=0.039), but there was no significant difference between the positive ASST group and negative one. It inferred that leptin played a part in both autoimmunity urticaria and non-autoimmunity urticaria and it might be more important in the former. (6) Either IgE positive or IgE negative group's leptin level was lower than that of control group (P=0.025, P=0.008). But there was still no difference between the two groups. It implied that leptin produced effects in both urticaria and it might be more significant in IgE negative urticaria.The effects of leptin in CIU were possibly related to following mechanisms.(1) Leptin broke the ballence of Th1/Th2 and suppressed the production of Th2 cytokines by regulating the secretion of cytokines. The decreasing of leptin level would convert the secretion of cytokines to Th2 immune response, then lead to the morbility of chronic urticaria. (2)By the up-regulation of bcl-2, leptin would step down the apoptosis of T cells including autoreactivity T cells, thereby enhanced the sensitive to autoimmunity diseases. (3) The decreasing of leptin also might influence humoral immunity, of which autoantibody IgG1 synthetized by B cells would increase, thus aggravate chronic urticaria.The secretion of leptin was not only influenced by body weight, gender, autorhythm, but also regulated by cytokines and neuroendocrine. In present study, the decreasing of leptin level of CIU patients indicated that leptin was consumed in vivo to some extent. But the exact mechanism is unknown.In summary, above results suggested leptin played an important role in the pathogenesy of CIU. Hence, this research will provide a new way for the treatment of CIU.