title: Preface.
authors.affiliation: Division of Immunology and Allergy, Department of Pediatrics, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada. croifman@sickkids.ca
authors.forename: Chaim M
authors.initials: CM
authors.lastname: Roifman
mesh_terms: D006086:Graft vs Host Disease / Q000209:etiology / Q000276:immunology*; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000276:immunology / Q000628:therapy*; D033581:Stem Cell Transplantation / Q000009:adverse effects / Q000379:methods*; D013234:Stem Cells / Q000166:cytology / Q000276:immunology*