CML nonreactivity after kidney transplantation.

THE occurrence of donor-specific cellmediated lympholysis (CML) nonreactivity in unrelated and related donor-recipient combinations has been documented in several reports." Our results showed that the development of CML nonreactivity correlated significantly with good graft function. Furthermore, we found that compatibility for the Η LA-Β locus antigens between donor and recipient and sex match in male patients predisposed to the occurrence of CML nonreactivity.' In this study we investigated whether the absence of CML reactivity of recipient lymphocytes towards the specific kidney donor splenocytes could be due to lack of helper cells. Our results indicate that even after Stimulation of the recipient lymphocytes towards a pool of stimulator cells, no cytolytic activity against the donor cells could be observed. However, when such pool-stimulated effector cells were tested on each cell of the pool individually as a target, absence of cytolytic activity was observed in effectortarget cell combinations that were HLA-B identical.