Study On Dermatophagoides Recognition And Uptake By Umbilical Cord Blood Derived Langerhans Cells

Atopic dermatitis(AD) is a chronic, inflammatory skin disorder, which is characterized by intense pruritus, skin dryness and eczematous leisions. AD is a multifactorial disease that arises as a result of the interaction between environmental, genetic factors, epidermal barrier dysfunction, disregulation of the immune response and and microbiota disequilibrium.About 60% of AD patients have high level of serum IgE. Dermatophagoides is the most common allergen in AD patients. In China, Der p 1 (Dermatophagoides pteronyssinus allergen 1) and Der p2 (Dermatophagoides pteronyssinus allergen 2) are the dominant allergens in patients with dermatophagoides allergy. Der p2 sIgE is positive among 77% of AD patients.However, the role of dermatophagoides in AD pathogenesis has not been fully elucidated.In AD patients, skin barrier dysfunction is often present in either the lesional or perilesional skin. The defective barrier allows entry of antigens via the skin, and creates a milieu that shapes the immuneresponse to these antigens. In case of the impaired skin barrier, epicutaneous sensitization(ES) is one of the main characteristics of AD. In the process of ES, LCs might play an important role in allergens uptake.. When TSLP is over-expressed in keratinocytes in mice, ES can be induced. Furthermore, TSLP acts as a potent stimulator of Th2 cytokines and IgE,the latter one take part in the patheogen of AD.Langerin is one of CLRs expressed on LCs, which could uptake polysaccharides such as glucan, fucose and N-acetylglucosamine.Our preliminary study may provided evidences for the uptake and endocytosis of dermatophagoides by Langerin through a couple of in vitro experiment.To demonstrate the recognization and uptaking of allergens by LCs through Langerin and the inducing of further immune response, we conducted a series of studies as follows.【Objective】(1) To study the correlation of Der p2 specific IgE with the severity of atopie dermatitis. (2) To investigate the phenotypic characteristics of CD34+ cells from umbilical cord blood derived human langerhans cells and CD 14+ monocyte derived human LCs in vitro. (3) To observe the recognition and uptake of Der p2 by umbilical cord blood derived LCs, and assessing LCs activation and maturation after Der p2 stimulation.[Methods] (1) 92 AD patients who met Hanifin & Rajika’s diagnosis standards were selected. SCORAD system was used to measure the severity of AD, and the specific IgE antibody against Dermatophagoides were detected at the same time. (2) CD 14 positive mononuclear cells and CD34 positive cells were isolated from peripheral blood and umbilical cord blood. These cell were cultured under specific cytokines circumstances for several days according to literature protocals, then were subjected to microscope observations and flowcytometry detection of CD la and Langerin. (3) Umbilical cord blood derived LCs were investigated as cell models for testing the recognition and uptaking studies of Der p2-Langerin interaction by using confocal microscopy and flow cytometry.[Results] (1) In the dermatophagoides sIgE-positive AD patients, SCORAD was significantly associated with dermatophagoides sIgE level. (2)In vitro derived LCs from peripheral blood and umbilical cord blood could express a certain number of CD1a and Langerin. (3) Umbilical cord blood derived LCs could recognized and uptaken Der p2, followed by CD80, CD86,CD83 and HLA-DR reduced expression.[Conclusions] We demonstrated that LCs surface molecules Langerin could recognize Der p2 via Langerin. After the stimulation of Der p2, LCs exhibited unmature characteristics, which remindd us the induced tolerance of LCs in steady-state.