T-Cell-Mediated Suppression of Hematopoiesis

Eight years ago, Hoffman and co-workers reported in the Journal that peripheral-blood lymphocytes from patients with aplastic anemia could suppress the growth of erythroid colonies from normal marrow.1 Concurrently, it was shown that removal of lymphocytes from aplastic marrow by treatment with antithymocyte globulin and complement or by gravity sedimentation partially restored the growth of granulocyte progenitors.2 These studies suggested that some cases of marrow failure were due to inhibition of marrow progenitor-cell growth by "autoreactive suppressor" T lymphocytes. However, it was also suggested that the observed inhibitory effects of lymphocytes from patients with aplastic anemia were due to allosensitization . . .