PROLIFERATION OF MACROPHAGE-LINEAGE CELLS IN THE BONE-MARROW, SEVERE THYMIC ATROPHY, AND EXTRAMEDULLARY HEMATOPOIESIS OF POSSIBLE DONOR ORIGIN IN AN AUTOPSY CASE OF POSTTRANSPLANTATION GRAFT-VERSUS-HOST DISEASE

A case of proliferation of CD68-positive macrophage-lineage cells in t he bone marrow accompanied by severe thymic atrophy associated with gr aft-versus-host disease (GVHD) in a boy given allogeneic bone marrow t ransplantation (BMT) is reported, A 7-year-old boy was treated for pos thepatitic severe aplastic anemia by BMT from his HLA-identical, mixed lymphocyte reaction-negative sister, After the transplantation his pe ripheral blood group converted to the donor type, However, the patient suffered from acute and chronic GVHD and slowly progressive anemia, a nd he died of multiple organ failure 21 months after BMT, At the autop sy diffuse and monotonous proliferation of CD68-positive macrophage-li neage cells was found to be replacing the blood-forming cells in the b one marrow, The thymus was almost empty of T lymphocytes, and remainin g strands of extremely atrophic epithelial cells showed focal cystic c hange. Extramedullary hematopoiesis was found in the spleen, Analyses of microsatellite markers suggested the hematopoietic cells in the spl een to be of donor origin.