THE modern era of bone-marrow transplantation was ushered in by the experiments of Jacobsen, Lorenz and their colleagues, who showed that mice could be protected against otherwise lethal irradiation by shielding of the spleen1 or by intravenous infusion of marrow.2 At first it was thought that this protective effect was due to a humoral factor.3 By 1956, however, several laboratories, using a variety of blood genetic markers, demonstrated that the protective effect against lethal irradiation was due to the colonization of the recipient marrow by donor cells.4 5 6 7An article on clinical marrow transplantation that appeared in . . .
Thomas et al. (1975) studied this question.