Cell-mediated immune responses in renal transplant recipients treated with cyclosporin and prednisolone with or without azathioprine.

The cell-mediated immune response was studied, using mixed lymphocyte reactivity (MLR) and cell-mediated lympholysis (CML) tests, in patients with well-functioning kidney grafts from living donors at 6 and 12 months and at 2-5 years after transplantation. The patients were allocated to treatment with cyclosporin A (CyA) and prednisolone (group A) or with CyA, prednisolone and azathioprine (group B). The MLR towards a third party were in the range of that of untreated controls while the anti-donor activities were reduced after 6 months in both groups. The CML activities in group A towards a third party were in the range of that of untreated controls at all times, while the anti-donor activities were decreased. By contrast, the CML activities in group B towards a third party were decreased during the first year and were in the range of that of normal controls at 2-5 years. The anti-donor CML activities were low at all times in group B. In summary, the two CyA protocols allowed the induction of donor-specific unresponsiveness within the first post-transplant year. The anti-third party activities were low during the first post-transplant year in recipients with triple therapy but not in those without azathioprine.