Quantitation of erythropoiesis by a new method. IV. Studies using 59Fe and DF32P simultaneously in haematological diseases

Quantitative assessment of erythropoiesis in haemolytic disease

Erythrokinetic parameters were estimated in 21 patients suffering from haemolytic disease using a mathematical model of iron kinetics. A proper definition of radioiron reflux from red cells to the plasma proved to be essential for an accurate estimate of effective and ineffective erythropoiesis in severe haemolytic conditions. Erythropoietic activity was increased in all the patients, with the marrow capable of sustaining erythropoiesis at about 6 times normal in hereditary spherocytosis and 3 times normal in autoimmune haemolytic anaemia. This proliferative effort was countered by an increase in ineffective erythropoiesis which was especially marked in hereditary spherocytosis.

Quantitation of erythropoiesis in myelomatosis

Quantitation of the erythropoiesis with radio-iron (59Fe) was applied to 9 patients with untreated myelomatosis. The method included blocking of the 59Fe reutilization by injection of non-radioactive iron. There was no uniform pattern in the Fe-kinetics values. The Plasma Iron Turnover (PIT) and the Red Blood Cell Iron Turnover (RBCIT) varied from subnormal to values markedly increased above upper normal limit. The calculated average Mean Red Cell Life time (MRCL) of erythrocytes was just below normal range. The mean Marrow Transit Time (MTT) was normal in the patients, despite subnormal venous haematocrit, indicating insufficient stimulation of the bone marrow. The renal function, measured as 51Cr-EDTA clearance, was found positively correlated to the RBCIT (r = 0.78, P less than 0.05). The results suggest that the previously demonstrated relationship between anaemia and renal failure in patients with myelomatosis is caused mainly by an inability of the bone marrow to produce sufficient red blood cells under the stress of anaemia related to the degree of renal impairment.