Anaemia and Leucopenia after Injection of Parental Strain Blood in F₁ Hybrid Mice Previously Treated with Sub-lethal Irradiation

Summary

The delayed lethal syndrome elicited by the injection of A-strain (i.e. parental) blood into (L × A)F₁ hybrid mice previously given a sub-lethal dose (500 r) of x-rays is accompanied by a sequence of events concerning the peripheral-blood picture, as follows: (1) the leucocyte level falls to essentially zero, makes an abortive attempt at recovery at about 7 days, then falls again, remaining at very low levels until the death of the animal. All control groups exhibited a continuous rise toward normal, beginning at about 7 days after irradiation. (2) Erythrocytes fell in a roughly linear fashion until death. At about 16 days, control groups showed marked reticulocytosis, which coincided with the beginning of the return toward normal erythrocyte levels.

The significance of these results as they concern the aetiology of homologous disease in lethally-irradiated mice treated with bone marrow is discussed. It is suggested that the differences observed in homologous disease initiated by bone marrow, lymphoid tissue (lymph node or spleen) or blood, may depend on the lymphoid/(myeloid and erythroid) cell ratio of the injected material. Possible causes of the observed anaemia are discussed.