Effect of Transfusion Polycythemia upon Bone Marrow Activity and Erythrocyte Survival in Man

1. The effect of transfusion polycythemia upon bone marrow activity and erythrocyte survival has been studied in 4 normal young adult males.

2. Plasma volumes did not change significantly throughout the period of study.

3. Total red cell masses increased to the "expected" levels, i.e., to the total of the subjects’ cells plus the transfused cells immediately after the transfusions. Thereafter these fell progressively, reaching the control levels in about forty days.

4. Survival of the infused cells was normal.

5. The subjects’ own red cell masses fell progressively at first. This was due to decreased erythropoiesis rather than to increased destruction. This is indicated by (a) no consistent significant elevation in hemolytic indexes; (b) change of the myeloid-erythroid ratio from normal values of 4 to 7:1 to about 20:1 two weeks post-infusion; (c) consistent decrease in circulating reticulocytes.

6. The depression of erythropoiesis was directly related to the quantity of red cells infused; almost complete cessation of red cell synthesis followed an increase of the red cell mass by forty per cent.

7. The depression of erythropoiesis was only temporary. As soon as the total circulating red cell mass returned to the pre-injection level, erythropoiesis proceeded at a normal rate.

8. No consistent changes in the circulating white blood cells, totals and differentials were noted.

9. Mild abnormalities in some liver functions were observed. Whether these should be attributed to the effects of the transfusions directly, or to the mild febrile responses experienced by the subjects shortly after the infusions cannot be stated with certainty at present.