Plasma Cell-like Dendritic Cells And LL37 In IgG4-related Diseases

Aim:To study the expression and function of plasmacytoid dendritic cells(pDCs)and LL37 in IgG4-related disease(IgG4-RD).Methods:We collected the peripheral blood from IgG4-RD patients without pre-treatment,and blood from sex-and age-matched healthy controls.Flow cytometry was performed to analyze the expression of pDCs inperipheral blood from IgG4-RD patients and healthy controls.The immunohistochemeistry technique were used to assess the quantity and location of pDCs in the involved tissues of IgG4-RD patients,then we used ELISA to measure the content of type ? interferon(IFN)in serum of patients and HCs;then,RT-PCR?ELISA was used to detect the expression of LL37,a peptide which is related to the activation of pDCs.Results:The frequencies of pDCs(CD123+CD303+)in IgG4-RD patients were significantly higher in the peripheral blood compared with healthy controls.In the tissues of IgG4-RD,the pDCs was highly expressed,and showed diffuse infiltration.The level of IFN-a was higher in serum in IgG4-RD patients;but for the LL37,both mRNA and expression level was lower in IgG4-RD compared to healthy controls.Conclusion:pDCs may play important role in the pathogenesis of IgG4-RD.In IgG4-RD patients,the pDCs were activated,secreted more type I interferon and migrated from blood into involved tissues.However,LL37 might not contribute to the activation of pDCs,its reduction in IgG4-RD needs to be further studied.