Leukaemia and anaemia in AKR/O mice. II. Role of the spleen as an erythropoietic organ during leukaemia development.

In order to study the role of the spleen in erythropoiesis during AKR/O leukaemogenesis, we have cultured bone marrow and spleen erythroid colony-forming units (CFU-E) and burst-forming units (BFU-E) from AKR/O mice (n = 40) with leukemia of varying severity and type of manifestation. Mice with leukaemia/lymphoma had reduced concentrations of bone marrow CFU-E and BFU-E as compared to healthy, age-matched AKR/O mice. The spleen content of CFU-E was increased, and highest in mice with a spleen size between 500 and 1000 mg. The largest spleens had a somewhat lower CFU-E content. Mice with the highest spleen CFU-E content most often had a normal PCV; however, 4/7 had a normal bone marrow CFU-E concentration. During AKR/O leukaemogenesis with development of spleen enlargement, the spleen may act as an erythropoietic organ, and contribute to maintaining a normal PCV. This may be a temporary ability which is reduced or lost with further progress of the disease.