[Studies on the pathogenesis of congenital hypoplastic anemia (Diamond-Blackfan syndrome)].

CFU-E growth from fractionated bone marrow cells of five patients with Diamond Blackfan syndrome was studied. In all patients, CFU-E growth was reduced in mononuclear cell rich fraction. In two patients out of five, CFU-E growth was returned to normal by the depletion of E-rosette forming cells of monocytes from mononuclear cell rich fraction. In the patient whose CFU-E growth returned to normal by the depletion of E-rosette forming cells, cocultivation between bone marrow buffy coat cells and autologous bone marrow E-rosette forming cells resulted in a significant decrease of CFU-E growth, and there was a significant increase in CFU-E growth by the treatment of OKT 4. In other three patients out of five, there was no significant increase in CFU-E growth by the depletion of monocytes and/or E-rosette forming cells. It is concluded that immunologic causes such as cellular factors may play a role, at least in part, on the pathogenesis of Diamond-Blackfan syndrome.