Study on pathophysiological mechanism of autoantibody production in pemphigus

点击翻译按钮获取中文摘要

Mechanisms of tolerance break against desmoglein 3 (Dsg3) in patients with pemphigus vulgaris (PV) producing pathogenic anti-Dsg3 IgG autoantibodies are unclear. In this study, we had dual approaches using human materials of PV patients and a mouse model for PV.To examine cellular mechanisms underlying the autoantibody production in PV patients, we have successfully developed an Enzyme-Linked Immunospot (ELISPOT) assay which was able to detect Dsg3-specific autoimmune B cells quantitatively. The in vitro anti-Dsg3 Ab production was abolished when CD4^+ cells were depleted or when anti-HLA-DR or anti-HLA-DQ monoclonal Ab was added to the cultures, suggesting the important role of HLA class II-restricted CD4^+ T cells in the autoAb production in PV.Using a novel PV mouse model involving Dsg3 knockout mice, we investigated the mechanisms of tolerance loss against Dsg3. Adoptive transfer of Dsg3^<-/-> splenocytes immunized with recombinant mouse Dsg3 to Rag2^<-/-> recipient mice expressing Dsg3 resulted in the stable production of anti-Dsg3 IgG and development of PV phenotypes including oral erosions with suprabasilar acantholysis. When purified T and B cells from Dsg3^<-/->, Dsg3^<+/-> or Dsg3^<+/+> mice were mixed with various combinations and transferred to Rag2^<-/-> mice, pathogenic anti-Dsg3 IgG production was observed only with a combination of Dsg3^<-/-> T and Dsg3^<-/-> B cells but not with the other combinations. These results suggest that loss of tolerance against Dsg3 in both B and T cells is important for the development of autoimmune state of PV.