Altered Expression Of TLR7 In Basophils Of Patients With Allergic Rhinitis

ObjectiveRecently,it has been reported that Toll like receptor 7 agonists can improve allergic rhinitis(AR)symptoms by up-regulation of Th1 cytokine release and suppression of Th2 cell functions.However,little is known about the expression of TLR7 in basophils of AR.Therefore,we detected the expression of TLR7 in basophils of AR and influence of allergens on TLR7 expression,which provided experimental data for the role of TLR7 in basophils in the pathogenesis of allergic rhinitis.MethodsIn this study,cultured KU812 cells were incubated with various concentrations of Der p 1(Dermatophagoides Pteronyssinus 1),OVA(Ovalbumin)and DSR6434(Ligand of TLR7),IL-31(Interleukin-31),IL-33,IL-37,TSLP(Thymic stromal lymphopoietin),plasma from HC,DAE,ASWAE and plasma from AR for 30 min,2 h and 16 h at 37?,then collect cells and supernatant.Cells were resuspended in PBS for flowcytometric analysis to detect TLR7 expression,and some cells in Trizol for qPCR to detect TLR7mRNA expression,the culture supernatant was collected for ELISA to determine the levels of IL-6 and IL-13.A total of 46 AR patients and 23 healthy control(HC)subjects were recruited for the study and the blood from each patients and HC were collected.AR patients need to stop all antiallergic drugs at least two weeks ago and did not have other allergic diseases.Flow cytometry analysis was used to detect the expression of TLR7 in peripheral blood basophils following allergens of DAE(Dermatophagoide allergen extract),ASWAE(Artemisia sieversiana wild allergen extract)and PPAE(Platanus pollen allergen extract)challenge.ResultsAllergens Der p1 and OVA provoked upregulation of TLR7 protein expression and mRNA levels in KU812 cells,and stimulated the production of IL-13.Dermatophagoide allergen extract,Artemisia sieversiana wild allergen extract,IL-31,IL-33,IL-37 and TSLP provoked elevation of IL-6 release from KU812 cells following 2 h incubation period.Compared with HC subjects,the percentages of TLR7~+CCR3~+cells,TLR7~+CD123~+HLA-DR~-cells and TLR7~+CCR3~+CD123~+HLA-DR~-cells in blood granulocyte cell populations of the patients with AR was increased.The percentage of TLR7~+CCR3~+cells,TLR7~+CD123~+HLA-DR~-cells and TLR7~+CCR3~+CD123~+HLA-DR~-cells in blood mononucleated cell populations of the patients with AR was increased,MFI(Mean Fluorescence Intensity,MFI)of TLR7 expression in CCR3~+cells,CD123~+HLA-DR~-cells and CCR3~+CD123~+HLA-DR~-cells were enhanced,respectively.ConclusionsThe expression of TLR7+basophils of AR patients stimulated by DAE and PPAE was significantly increased.After KU812 cells were stimulated by the OVA and Der p1,the expression of TLR7 was significantly enhanced.DSR6434(TLR7 agonist)did not have an obvious effect on TLR7.AR may be related to the upregulation of TLR7expression by part of allergens,and IL-6 and IL-13 released by basophils maybe participate in this process.