IGHE and autoimmune disease: -similar to NRG-express chimeric human-mouse class II transgenes HLA-DRA/HLA-DRB1*0401 fused to the I-Ed MHC class II molecule-allow enhanced HLA-DR-matched HSC engraftment and subsequent human T cell and B cell development to study the development of autoimmune diseases-allow vaccine testing and generation of human IgM, IgG, IgA or IgE monoclonal antibodies