Pre-transplant immunological profile and risk factor analysis of post-transplant lymphoproliferative disease development: the results of a nested matched case-control study

Development of post-transplant lymphoproliferative disease (PTLD) is a majo r complication of organ transplantation. While immune mechanisms seem to pl ay a major role in the development of PTLD, how the immune system contribut es to the process of PTLD development or its regression remains unknown. Be tween 1990-1994, 303 organ transplant recipients were enrolled into a prosp ective study designed to analyze risk factors for PTLD. Using a nested case -control design, 9 PTLD and 18 control patients were matched for age, EBV s erological status at the time of transplantation, and, in most cases, for t he type of transplanted organ. The immunologic profiles of both groups were compared prior to and following transplantation Immune measures included a bsolute numbers of lymphocytes and of subsets of T, B and natural-killer (N K) cells as well as spontaneous NK-cell and in vitro generated LAK-cell act ivities. A consistent trend for higher levels at baseline as well as follow ing transplantation for almost all immune parameters was observed in patien ts who developed PTLD, A high absolute count of activated NK cells (CD56+DR +) at baseline was found to be a significant predictor of PTLD development. The immunologic profile of patients who developed PTLD was consistent with pre- as well as post-transplant chronic immunologic stimulation, and not i mmunosuppression. In the PTLD group, 3 patients had pre-transplant autoimmu ne hepatitis and one had primary biliary cirrhosis, which suggests that the underlying presence of certain autoimmune disorders in organ transplant re cipients might predispose to PTLD development.