In Vivo Localization of Heterologous Anti-erythrocyte Antibodies in the Rat Bone Marrow and Their Effect on the Proliferative Capacity of Immature Erythroid Cells.

p ATIENTS with acquired auto-immune hemolytic anemia associated with a decreased red cell production have been reported by several authors.1-5 We have observed such cases among patients with acquired auto-immune hemolytic anemia due to incomplete antibodies of the warm variety. There have been many reports6 ’ suggesting the sensitization and damages of erythroblasts in the bone marrow by anti-erythrocyte antibodies. Recently Yunis and Yunis1#{176}have demonstrated A1, A2 and B receptor on orthrochromatic and basophilic normoblasts. These results suggest that anti-erythrocyte antibodies not only sensitize circulating red cells but also exert some cytotoxic effects on nucleated red cells in the bone marrow. However, little attention has been so far directed to the localization of anti-erythrocyte antibodies in the bone marrow and their effect on immature erythroid cells. By means of the P31-labeled antibody method, the in vivo localization of heterologous anti-erythrocyte antibodies was determined in the rat bone marrow. The effect of anti-erythrocyte antibodies on the proliferative capacity of nucleated red cells was studied in vitro by the incorporation of tritiated thymidine.