Figure 3.

The onset of immune-mediated thrombotic thrombocytopenic purpura (iTTP). ADAMTS13 is endocytosed by antigen-presenting cell [in this figure, dendritic cell (DC)] and processed to peptides that are subsequently loaded on MHC-II molecules. As described previously, ADAMTS13-derived peptides FINVAPHAR and ASYILIRD were found to be presented on HLA-DRB1*1101 and HLA-DQB1*03, respectively. In the case of presence of specific autoreactive CD4⁺ T cells, the complex MHC-II/peptide will be recognized by TCR, which will cause the activation of the CD4⁺ T cell. Such activated CD4⁺ T cells will then provide help to autoreactive B cells that will result in a production of ADAMTS13-specific auto-Abs.