Expression And Significance Of CRTH2 Receptors On T Lymphocytes In Peripheral Blood Of Children With Atopic Dermatitis

Objective Chemoattractant Receptor-Homologous Molecule(CRTH2)belongs to the G protein-coupled seven trans-membrane domain receptors,mainly expressed on Th2cells.It is also expressed on Tc2 cells,eosinophils,basophils and mononuclear cells surface.Its ligand is prostaglandin D2(PGD2).CRTH2 could mediate chemotaxis of Th2 cells,Tc2 cells,eosinophils,basophils and so on.It can also increase secretion levels of Th2 cytokines,inhibit Th2 cell apoptosis.As a result,it promotes the development of allergic inflammation.Expression of CRTH2 receptors can aggravate the symptoms of the patients with allergic rhinitis and asthma,and CRTH2 receptor antagonists can improve the clinical symptoms of allergic rhinitis and asthma.Now,CRTH2 receptor antagonistic agents have been used in allergic rhinitis and asthma clinical treatment,or are currently being tested in clinical trials.However,the pathological mechanisms of CRTH2 receptors in atopic dermatitis(AD),especially in children with atopic dermatitis,is not completely clear.The purpose of this study is to investigate the expression and significance of CRTH2 receptors on T lymphocytes in peripheral blood of children with AD.Methods We choosed 22 AD patients from department of dermatology and department of allergy and immunology,and we choosed 30 children with normal physical examination findings from June 2015 to October 2015.We recorded the general situation,family history,SCORAD score,serum total IgE,serum eosinophils level and allergen information.We used flow cytometry to detect the proportion of CRTH2~+CD4~+T cells and CRTH2~+CD8~+T cells.Besides,we detected the levels of IL-4,IFN-?secreted by CRTH2~+CD4~+T cells and CRTH2~+CD8~+T cells in two groups.Then,we analyzed the correlation between the proportion of CRTH2~+CD4~+T cells and family history,SCORAD score,serum total IgE,serum eosinophil levels and allergen information.CRTH2~+CD8~+T cells are the same.We used flow cytometry and CCK-8proliferation assay to detect the proportion changes of CRTH2~+CD4~+T cells and CRTH2~+CD8~+T cells after dust mites stimulation.Results The average percentage of CRTH2~+CD4~+T cells in peripheral blood in AD group was higher than that in the control group(P<0.05),and there was no significant difference in the proportion of CRTH2~+CD8~+T cells in two groups(P>0.05).There was a positive correlation between serum IgE level,edema/infiltration/papules symptom scores,exudation/crusting symptom scores and the proportion of CRTH2~+CD4~+T cells.CRTH2~+CD4~+T cells secreted high amounts of IL-4,but not IFN-?.CRTH2~+CD8~+T cells secreted both IL-4 and IFN-?.The percentage of CRTH2~+CD4~+T cells,CRTH2~+CD8~+T cells in PBMC after dust mites stimulation increased,and the difference percentages of CRTH2~+CD4~+T cells in AD group were more dominant than that in the control group(P<0.05).Conclusions CRTH2 receptors are expressed on T lymphocytes in peripheral blood of both children with atopic dermatitis and normal children.The level of CRTH2~+CD4~+T cells may reflect the severity of the clinical symptoms of AD children.CRTH2~+CD4~+T cells are involved in the pathogenesis of children atopic dermatitis,CRTH2 receptors or CRTH2~+CD4~+T cells may be a potential target for the treatment of AD in the future.