PROLONGED SECRETION OF IL-15 IN PATIENTS WITH SEVERE FORMS OF ACUTE GRAFT-VERSUS-HOST DISEASE AFTER ALLOGENEIC BONE-MARROW TRANSPLANTATION IN CHILDREN

Graft-versus-host disease (GVHD) is one of the most common and fatal c omplications that follows allogeneic bone marrow transplantation (BMT) . Donor origin T cells are responsible for the initiation of GVHD. In this report, we demonstrate that conditioning regimens for BMT resulte d in elevated serum levels of interleukin-15 (IL-15), which reached ma ximum levels within 15 days and returned to basal levels within 25 day s after allogeneic BMT, in all patients examined. Thereafter, circulat ing IL-15 was detected only in patients with grade III or IV acute GVH D with gut involvement. In contrast, IL-2 was not detected at any time in these patients. Since IL-15 is able to activate antigen-stimulated T cells and natural killer (NK) cells, IL-15 may play an important ro le in the development of severe forms of acute GVHD. (C) 1998 Elsevier Science Ireland Ltd.