Organ transplantation: a practical triumph and epistemologic collapse.

T THE November 1970 meeting of the American Philosophical Society, Jonathan Rhoads organized and chaired a session on transplantation that consisted of five formal papers (1–5). By the time of this meeting, kidney, liver, heart, and pancreas transplantation already had been accomplished in humans and the first successful bone marrow transplantations had been recorded (Table 1) (6–10). But the results with these procedures were not yet good enough to generate much enthusiasm. Moreover, it was not clear how to make things better. One reason was that workers in the burgeoning special field of transplantation immunology already had been disoriented by a conceptual error. As early as 1962, the mistaken conclusion had been reached “by consensus” that the engraftment of organs involved mechanisms fundamentally different from those of successful bone marrow transplantation. Although the error was a seemingly innocuous one, it became the basis of a false paradigm that precluded the orderly development of transplantation immunology, and limited progress in clinical transplantation almost exclusively to the development of more potent antirejection drugs.