Bone marrow transplantation: a review of delayed complications.

In one and one-half decades, marrow transplantation has become a life-saving procedure for an ever-increasing number of patients. With continued observation, however, it became apparent that marrow transplantation as used presently is associated with significant acute, delayed, and chronic toxicity. These complications may be related to chemo- or radiotherapy used in conditioning for transplantation, to immunosuppressive treatment given after transplantation and to the immunodeficiency associated with transplantation and the development of GVHD. Attempts need to be made to develop less toxic conditioning regimens. Most importantly, however, we need to learn more about mechanisms of graft-host interaction in order to eliminate the problem of GVHD and to accelerate the recovery of immunocompetence in allogeneic chimaeras.