The relationship between human spleen and blood erythroid burstforming units (BFU-E)

The influence of splenectomy on erythroid burst colony formation by peripheral blood mononuclear cells from 10 patients (four with hereditary spherocytosis, two with beta-thalassaemia major, two with Hodgkin's disease and two with idiopathic thrombocytopenic purpura) was studied. In every instance splenectomy was followed by a lowering of blood BFU-E. The post-splenectomy levels ranged from 0 to 30% of the preoperative levels. Mononuclear cells from the spleens of eight patients were cultured and found to contain numerous BFU-E. The total quantity of BFU-E in the whole blood and in the spleen of the patients was generally of the same order of magnitude. The number of splenic BFU-E did not correlate with spleen size. Splenic BFU-E differed from peripheral blood BFU-E in that they were more sensitive to erythropoietin (Ep) and in that they failed to respond to burst promoting activity (BPA) produced by preincubating the spleen mononuclear cells with phytohaemagglutinin M (PHA). In contrast, media conditioned by PHA-treated spleen cells contained BPA active on peripheral blood BFU-E from normal individuals. These data suggest that the spleen may have an influence on the numbers and functional properties of BFU-E.