Bone Marrow Studies in Myelomatosis

The percentage of fat-cell areas in bone marrow particles from 22 patients with untreated myelomatosis was estimated. In only 1 patient was the mean fat cell area below 25 % of the bone marrow area measured. A negative correlation was found between the area of fat cells and plasma cells, indicating a displacement of the fat cell area by the plasma cells. 28 % of the patients had empty bone marrow deposits of iron. However, based on a normal iron saturation of S-transferrin and a normal sideroblast count in the bone marrow, the supply of iron to the erythropoiesis was considered sufficient. All patients but one had normoblastic bone marrows. Using a deoxyuridine suppression test in 10 patients, no biochemical defect could be demonstrated. To judge from the correlation coefficient a minor degree (9–14 %) of the variation in Hb values could be predicted from the cellularity in the bone marrow while a major degree (70 %) could be predicted from the renal glomerular filtration rate. The results do not support a displacement of blood-forming elements, iron deficiency, vitamin B₁₂ or folic acid deficiency to be of general significance in the pathogenesis of anaemia, but agrees with a causal relationship between anaemia and renal failure.