Enlargement of the human spleen in graft-versus-host disease.

The spleens of 49 patients who had undergone allogeneic bone marrow transplantation for leukemia were compared at autopsy to determine the pathological changes associated with graft-versus-host disease (GVHD). The only significant finding was an increase in weight of about 1.7 times that of spleens from patients without GVHD. This was not explained by differences in the patients' sex, length of survival after transplantation, presence of infection, or liver pathology. On histological examination, there was no detectable increase in congestion, siderosis, or numbers of lymphocytes, macrophages, antigen-presenting cells, blast cells, pyknotic cells, plasma cells, or hemopoietic cells to explain the increase in spleen weight. On the contrary, there was actually a reduction in CD8+ T lymphocytes. No proliferative phase of GVHD could be identified, possibly due to a lack of specimens examined less than 8 days after transplantation and to prophylactic measures undertaken to minimize GVHD. The pathogenesis of splenomegaly in human GVHD is unclear.