Intracellular and Renal/Myocardial Tissue Concentrations of Cyclosporine A (CsA) and Rejection Frequency Following Transplantation

The primary objective is to investigate intralymphocyte concentrations of CsA in renal and heart transplant recipients to elucidate the association between the intracellular concentration and efficacy (rejection episodes and histology) in transplanted patients on CsA based immunosuppressive therapy.

The primary objective is to investigate intralymphocyte concentrations of CsA in renal and heart transplant recipients to elucidate the association between the intracellular concentration and efficacy (rejection episodes and histology) in transplanted patients on CsA based immunosuppressive therapy.

Secondary objectives are to investigate associations between intralymphocyte concentrations and whole-blood concentrations of CsA, renal tissue concentrations and nephrotoxicity, heart tissue concentrations and cardiotoxicity with CsA based immunosuppressive therapy in transplanted patients. In addition, this study aims to validate the use of quinine as a probe for determination of CYP3A4 activity in transplanted patients as well as proteomic-based urine analyses as a screening tool for acute rejection episodes in transplanted patients.

Inclusion Criteria:

1. Renal or heart transplant recipients scheduled to receive CsA as part of their immunosuppressive therapy at the time of transplantation.
2. 18 years of age or older.
3. Signed informed consent.

Exclusion Criteria:

1. Known contraindications for renal or heart biopsies, respectively, at the time of inclusion.
2. Concomitant treatment with: diltiazem, verapamil, phenytoin, carbamazepine, fluconazole, ketoconazole, erythromycin, clarithromycin.