title: Thymic involution with loss of Hassall's corpuscles mimicking thymic dysplasia in a child with transfusion-associated graft-versus-host disease.
abstract: A 7-year-old leukemic girl developed pancytopenia following chemotherapy and was given several transfusions of nonirradiated blood. Within 2 weeks she developed a maculopapular rash, fever, abnormal liver function, diarrhea, and wasting. She became septic and died 6 weeks later. Transfusion-associated graft-versus-host disease (GVHD) was suspected clinically. At autopsy, changes diagnostic of GVHD were present in the skin and liver. The remarkable feature of the case was the histopathology of the thymus, which was morphologically "dysplastic," i.e., minute, lymphoid depleted, devoid of a corticomedullary demarcation, and completely lacking in Hassall's corpuscles. These changes were virtually identical to those seen in the thymus of children with severe combined immunodeficiency disease (SCID). There was no evidence of preexisting immune deficiency. There is compelling experimental evidence that GVHD can produce changes in the thymus that are identical to those of "thymic dysplasia." These observations have led to the hypothesis that immunodeficiency associated with GVHD may stem, in part, from injury to thymic epithelium resulting in defective T cell maturation. As a corollary of this hypothesis, it has been suggested that the pathogenesis of some forms of SCID may involve GVHD-associated injury to the thymus by a maternal allograft acquired in utero. This report further documents thymic pathology in human GVHD and discusses these changes in the light of these ideas.
authors.affiliation: Department of Pathology, University of Manitoba, Winnipeg, Canada.
authors.forename: J G
authors.initials: JG
authors.lastname: Gartner
mesh_terms: D000208:Acute Disease; D002648:Child; D005260:Female; D006086:Graft vs Host Disease / Q000209:etiology / Q000473:pathology*; D006801:Humans; D007938:Leukemia / Q000628:therapy; D013950:Thymus Gland / Q000473:pathology* / Q000648:ultrastructure; D065227:Transfusion Reaction