ilar finding was observed for patients having CNa values out of the range of 12102 pmol/mg/min corresponding to the 15th and 85th percentiles as compared to patients displaying CN-a values within this range. On the basis of these results, we chose to compare the long-term outcomes of patients who displayed CN-a values within the range of 
12102 pmol/mg/min versus patients who exhibited at least one CN-a value outside this range during the first 24 months after transplantation. Adverse Events Related to Over-immunosuppression Because low CN-a levels might reflect an over-immunosuppression, we compared the onset of events known to be associated with over-immunosuppression, such as malignancies and infections, between patients displaying or not CN-a levels below the lower threshold of 12 pmol/mg/min during the first 24 months after transplantation. Of the 107 lung-transplant recipients in this study, 1 patient, who displayed an Epstein-Barr virus-induced lymphoma before any CN-a measurement was made, was not considered for the evaluation of the relationship between CN-a and malignancies. A total of 103 measurements of calcineurin activity were performed in the group of patients free of acute rejection and of 74 in the group of patients with acute rejection before the occurrence of this event. Calcineurin Activity in Lung Transplantation Calcineurin Activity and Overall Survival Of the 107 patients enrolled in the study, 25 patients died during follow-up. At this time of the evaluation, no significant difference was found in the overall survival between the 2 groups of patients exhibiting CN-a levels within or outside of the range of 12102 pmol/mg/min. This relationship should be reassessed after a longer period of follow-up. Discussion The activity of calcineurin measured in the PBMCs of allograft recipients who received inhibitors of calcineurin has been shown to be an index of T cell activation and a marker for graft-versus-host disease. It was thought that a high CN-a reflected poor immunosuppression whereas a low CN-a reflected potent immunosuppression. Therefore, our working hypothesis, for the present study, was that the level of 11325787 CN-a can predict the degree of immunosuppression after lung transplantation, and, thus, be useful for predicting both the occurrence of rejection, related to an inadequate immunosuppression, and the development of severe PR619 complications, related to excessively potent immunosuppression. However, we report here that patients who displayed extreme CN- Calcineurin Activity and Cyclosporine Blood Levels Calcineurin Activity in Lung Transplantation a values, either high or low values, were mainly those patients who developed acute rejection and had an altered pulmonary function. These observations led us to define an optimal activity for CN between two thresholds, 12 and 102 pmol/mg/min. Patients who had CN-a values within this range had a significantly higher survival without BOS. Furthermore, the occurrence of malignancies and viral infections was significantly lower in patients who exhibited CN-a values higher than 12 pmol/mg/min. With the introduction of more potent immunosuppressive agents and newer combinations during the last ten years, patient and graft survivals 12149260 have dramatically increased following most types of solid organ transplantation. However the incidence of post-transplantation infections and cancer also has increased. It was thought that potent immunosuppression, as reflected by the occurrence of