Objective: Lymphocyte immunosuppressant sensitivity test (LIST) is useful for predicting the pharmacological efficacy of immunosuppressive agents. In this study, the pharmacological efficacy of cyclosporine was estimated by LIST before and after renal transplantation.
Methods: Lymphocyte immunosuppressant sensitivity test was performed by the 3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide (MTT) assay before and at 1, 3, and 12 months after transplantation in 19 consecutive renal transplant recipients.
Results: There was wide intersubject variability in cyclosporine IC50 before transplantation [Mean (SD) of 593.9 (1067.6) ng/mL]. This variability worsened 1 month after transplantation [525.7 (1532.7) ng/mL] but decreased at 3 months (193.5 (347.9) ng/mL) and 12 months (75.4 (95.4) ng/mL). In this small study, observed differences in IC50 values for the individual subjects at various time intervals was not associated with the occurrence of rejection, graft loss, and infection episodes.
Conclusion: Lymphocyte sensitivity to cyclosporine assessed by the LIST assay showed a high level of inter-subject variability particularly before and 1 month after transplantation. The observed difference in IC50 values was not associated with clinical outcome in this small study.