Change and significance of peripheral blood of patients with alopecia areata IL-17~+T cell level
|Beijing University of Traditional Chinese Medicine
|Alopecia areata IL-17 γδT cells Th17cells T cell subgroup
Alopecia areata is a type of sudden localized alopecia with normal local skin, no rational symptom and a few scattered large area of hair loss. Alopecia areata is one of the common dermatological diseases and it is difficult to be distinguished from telogen effluvium. Alopecia Universalis and Alopecia Totalis with hair loss more than50%are considered as refractory diseases. Etiology and pathogenesis of alopecia areata are currently unknown; some of the relevant factors could be genetic factors, immunological imbalance, psychological factors and environmental factors. Scholars believe that alopecia areata which is based on patient’s genetic predisposition and induced by a variety of complex factors, is an autoimmune disease with immune developed against those follicle cells in the growth period.Thl7cell is a new type of CD4+T cells found recently. Its characteristic cytokine belongs to IL-17family that shows strong pro inflammatory impact. It has been found in recent years that functions Thl7cells possess like extracellular defense, antineoplastic and anti-rejection functions play important roles in autoimmune diseases. y8T cells are major components of forming IL-17cells and they can quickly recognize and respond to TCR signals. γδT cells are rich in epithelial tissue and being induced by IL-1β and IL-23, part of them can produce IL-17and worsen the disease by increasing the degree of inflammation. Alopecia areata, as a common autoimmune disease,could be similar with psoriasis. Its pathogenesis is closely dependent on IL-17cytokines and IL-17γδT cells. However, there is still lack of research study on alopecia areata and IL-17.The study was divided into two sections:Section I:Literature ReviewFrom a modern medicine perspective, the first section reviewed a variety of etiological factors from genetic, immunological and endocrine aspects. It is followed by exploring etiology, differential treatment and other aspects of alopecia areata in ancient records of Chinese medicine for a more comprehensive study.Section Ⅱ:Experimental StudyObjective:To understand the relationship between alopecia areata and IL-17+cells and to clarify the classification source of such TCR cells.Methodology:1. The experiment was carried out using flow cytometry to analyze the antigen of CD3, CD4and CD8in peripheral blood of both alopecia areata patients and healthy people. Total lymphocyte counts, percentage of T lymphocytes, CD4T lymphocytes and CD8T lymphocytes, CD4/CD8ratio were compared to clarify the relationship between alopecia areata and immune function. 2. Using flow cytometry, double mark detection of IL-17A and TCRyS in peripheral blood of alopecia areata patients and healthy people was done. By comparing the number of IL17+cells, γδ cells, IL-17+γδ+cells, IL-17-+1γδ+cells and the IL-17-γδ+to γδ+ratio between alopecia areata patients and healthy people, it aimed to draw a clear correlation between IL-17+and alopecia areata and to identify the TCR source which secretes IL-17A cells.Experimental results:1. Alopecia areata patients have more peripheral lymphocyte counts than healthy people. There is also slight increase in T lymphocyte counts observed. However, there is no significant difference in number of CD4, CD8and CD4/CD8between healthy people and those with alopecia areata.2. Alopecia areata patients have significantly more IL-17+and IL-17+δγ+T cells than healthy people, but no difference in γδ+T cells between the two groups. In IL-17+cells, most cells are γδ phenotype. Alopecia areata group IL-17+γδ+takes a larger proportion in γδ+T cells than the healthy group, showing that there is a tendency of cell differentiation from γδT cells to IL-17+γδ+cells in alopecia areata patients.Conclusion:Alopecia areata is an autoimmune disease. IL-17+T cells play an important role in the pathogenesis of alopecia areata, in which the major phenotype of TCR are y8T.