Journal Article Hematopoietic stem cell transplantation Research Support, Non-U.S. Gov't 4-1BB 4-1BB Ligand Adaptive immunity Atypical SCID Autoimmune cytopenia CMV infection Case Reports DNA-Binding Proteins Enteropathy Epstein Barr virus HLA-DR HLA-DR Antigens HSCT Inborn errors of immunity Intestinal epithelial cells Invariant chain Lymphopenia MHC class II deficiency Mixed Chimerism Mucosal immunity RFXANK protein, human RFXAP protein, human Recurrent lymphoproliferation Research Support, N.I.H., Extramural Research Support, N.I.H., Intramural Secondary malignancy TNFRSF9 protein, human