Abstract
Lymphocyte immunosuppressant-sensitivity test (LIST) is useful to predict the pharmacological efficacy for renal transplant recipients just before transplantation. Generally, IC50 rate and bottom levels based on peripheral blood mononuclear cells(PBMCs)blastogenesis are used for evaluation of the efficacy of immunosuppressants. Kuzuya et al. reported the strong positive correlation bottom level of both cyclosporine(CyA)and tacrolimus(Tac)by flow cytometry method. In our institute, we have used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)method for LIST to date. In this study, we have evaluated the relationship between IC50 level and bottom level of CyA and Tac by MTT method in 21 healthy volunteers. All the participantsʼ CyA bottom levels were below 0％, so we thought 2-sigmoid curve pattern(blastogenesis and killing cells). On the other hands, Tac bottom levels were over 0％, so we thought 1-sigmoid curve pattern(blastogenesis). We made IC50 rate and bottom levels by least squares method. We have found statistically significant correlation between CyA-Tac bottom levels(r＝0.48, p＝0.027), however, there were no positive correlation were indicated in any other combinations. In order to evaluate the immuno-compromised status, in accordance with patientsʼ clinical courses, we have compared cytomegalovirus(CMV)reactivation/infection status and these pharmacological parameters. CMV reactivation/infection was diagnosed by CMV antigenemia method. However, there was neither positive correlation between IC50 levels nor bottom levels and CMV reactivation status after kidney transplantation〔CyA(CMV＋: n＝11, CMV−: n＝2)IC50: p＝0.344, CyA bottom: p＝0.927, Tac (CMV＋: n＝9, CMV−: n＝6) IC50: p＝0.141 bottom: p＝0.629〕. In CMV＋patient, CyAʼs average trough were 144.81±60.00 ng/mL(n＝11), and Tacʼs average trough were 4.58±1.16 ng/mL(n＝9). In future, we would like to examine what kind of phrarmacological parameter is useful for evaluating adequate immunosuppression status after kidney transplantation.
