'Recurrent' erythroblastopenia of childhood. An IgM-mediated RBC aplasia.

An anemia of childhood with reticulocytopenia and marrow RBC aplasia was found to be due to immune-mediated erythropoietic suppression. In vitro assays of marrow and peripheral blood erythroid progenitors indicated normal cell numbers that markedly declined when autologous serum or IgM was added to the cultures, but remained unchanged with autologous IgG or with autologous serum depleted of IgM. In contrast to "transient" erythroblastopenia of childhood, this anemia was recurrent, lasted longer, and seemed to be prednisone responsive.