Changes in Cellular Composition of the Lymph Caused by Ionizing Radiations

Erythrocytes appear in large numbers in the lymph of rats and dogs after massive exposure to x rays. The peak of endothelial fragility, as indicated by the erythrocyte counts in the lymph, is reached on the ninth to fourteenth day in rats and the eleventh to seventeenth day in dogs. In both species the erythrocyte count in the lymph frequently exceeds one million.

Diversion of erythrocytes into the lymph compartment causes a relative anemia; excessive destruction of erythrocytes, presumably related to extravasation and not to a direct irradiation injury, is responsible in part for the absolute anemia. It is suggested that similar changes may contribute to the anemia of leukemia and other blood diseases associated with capillary fragility.

The drop in lymphocyte counts in both lymph and blood is precipitous within 5 to 10 hours after irradiation. During the fourth to eighth hours after irradiation, injured and dead lymphocytes are present in the lymph in large numbers. During the recovery phase, the per cent of large lymphocytes in the lymph greatly increases, there are many abnormal large lymphoid cells and mitotic figures, and tissue mast cells appear in blood smears.

It is concluded that diversion of erythrocytes into the lymph caused by massive irradiation, if severe, becomes a self-aggravating process and leads to death.