RELATIONSHIP BETWEEN ERYTHROCYTE-TO-PLASMA DISTRIBUTION RATIO OF CYCLOSPORINE AND LYMPHOCYTE-PROLIFERATION IN RENAL-TRANSPLANT PATIENTS

Objective: The aim of this study was to examine the relationship betwe en erythrocyte-to-plasma distribution ratio of cyclosporin (CsA-EP) an d lymphocyte proliferation as an indicator of immunosuppressive activi ty in renal transplant patients. Methods: A total of 113 whole blood s amples obtained from 6 inpatients with renal transplantation were anal ysed. CsA concentrations in blood and plasma at trough were measured b y fluorescence polarization immunoassay using monoclonal antibody, lym phocyte proliferation in response to phytohaemagglutinin was evaluated by the fluorimetric derivatization method using ethidium bromide and the stimulation index (SI) was calculated. Results: There was no corre lation between CsA dose and trough levels (vs blood CsA, r(2) = 0.052; vs plasma CsA, r(2) = 0.054, n = 113). A significant negative correla tion between the SI and the CsA-EP was found in individual or all samp les (r(2) = 0.224, p < 0.0001, n = 113), whereas CsA trough levels in blood or plasma had no correlation with the SI. Conclusion: Although t he degree of contribution of CsA-EP to the SI was 22%, the CsA-EP is a more useful predictor of changes in immunosuppressive response than C sA concentration in blood or plasma. The adoption of the CsA-EP as a m onitoring index could be helpful in assessing the appropriateness of C sA immunosuppressive therapy.