LEUKAEMIA TREATED BY RADIATION 



J. F. LOUTIT 



Medical Research Council Radiobiological Research Unit, 

 Atomic Energy Research Establishment, Harwell, England 



The discussion of this subject will be confined to work on leukaemia in the 

 mouse. It is true that in the last year or so similar studies have been made 

 on the leukaemia in man but in this field our laboratory has played as yet 



no part. 



The work on mice stemmed from the observations by Jacobson and his 

 groupi that mice which had received a lethal dose of X-rays might recover 

 following suitable treatment. The treatment consisted of implanting, under 

 anaesthesia, into the peritoneal cavities of the mice, spleens from normal 

 animals. Lorenz et al.^ carried the observations further, demonstrating that 

 suspensions of cells from bone marrow administered by injection after the 

 irradiation were also effective as therapy. In Lorenz's hands injections by 

 the intravenous route gave better results than those given intraperitoneally; 

 and successful results were obtained in mice, not only when homologous 

 bone marrow from mice of different strains but also when heterologous 

 bone marrow from animals of a difTerent species, guinea-pigs, was injected 

 intravenously. It was later shown by Congdon and Lorenz^ that rat bone 

 marrow, as well as guinea-pig marrow, was effective. 



Naturally, these very striking results led to the conclusion that the normal 

 bone marrow or spleen, given as therapy, contained a humoral agent which 

 caused an accelerated recovery of the irradiated mouse's own haemopoietic 

 tissue. It was inconceivable, on the basis of the laws of tissue transplantation, 

 that foreign material which had been injected could be a viable graft, which 

 would multiply and function and thereby save the irradiated animal's life. 

 However, when we entered the field sometime after Jacobson and Lorenz, 

 we set out to see whether, under the very special circumstances following a 

 lethal dose of X radiation, the normal laws of tissue transplantation did in 

 fact hold. 



After accumulating a certain amount of more or less indirect evidence 

 which would support an hypothesis involving the uptake of the injected 

 cells as a graft, and their subsequent function, we were able to show, as did 

 others at about the same time, that in fact the massive dose of X-rays — 

 normally the lethal dose — had destroyed the animal's capacity to reject 

 foreign cells, which in fact flourished and continued to keep the animal alive. 



The evidence from our laboratory"* • ^ indicated that not only was the bone 

 marrow of the irradiated animal recolonized by the injected cells but so were 

 the lymphoid tissues. Given that the recovery was due to the recolonization 

 of the host's depopulated haemopoietic tissues with cells from a normal 



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