Clinical assessment of trough levels for monitoring of rejection in cyclosporine-treated kidney transplant recipients.

We evaluated whether trough cyclosporine (CYA) level monitoring was useful in the diagnosis of rejection within 2 weeks after transplantation. Rejection occurred in 14 out of 17 patients (82.3%) treated with CYA, mizoribine (MZR) and prednisolone (Pred) when trough CYA levels dropped below 70 ng/ml, suggesting the importance of trough level monitoring. When anti-lymphocyte globulin (ALG) was added to the 3 above-mentioned drugs, however, rejection occurred in only 1 patient (6.7%) and 2 patients (13.3%), respectively, within 1 week and 1-2 weeks after transplantation, suggesting that trough level monitoring is less important in patients treated with these 4 drugs.