Monitoring Concentration and Pharmacodynamic Effects of Tacrolimus in Peripheral Blood Lymphocytes of Kidney Transplant Recipients

Study Overview
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Brief Summary
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Therapeutic drug monitoring (TDM) of immunosuppressive drugs is used to improve the immunosuppressive effect while minimizing the toxicity related to exposition to high serum levels. Although TDM is widely used in clinical practice, a significant number of kidney transplant recipients have acute allograft rejection in the first year after transplantation. To improve the use of immunosuppressive drugs, new approaches of TDM have been developed. Monitoring drug concentrations at lymphocytes of peripheral blood is considering promising because it indicates the availability of the drug directly in the target sites of immunosuppression. The present study intends to establish the concentration profile of tacrolimus in the peripheral blood in parallel with the concentration profile inside T and B lymphocytes of peripheral blood of kidney transplant recipients, and correlates them with the expected pharmacological effects. The pharmacological effects of tacrolimus in calcineurin dependent and calcineurin independent (mitogen-activated protein kinase (MAPK) dependent) activation pathways will be assessed by measuring activated nuclear factor of activated T cells (NFAT) and p38, respectively, by flow cytometry. The expression of interleukin (IL) - 2 and IL-10 by T and B lymphocytes, respectively, will be also used to monitoring the pharmacodynamic effects of tacrolimus.

Official Title
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Monitoring Intracellular Concentration and Pharmacodynamic Effects of Tacrolimus in Peripheral Blood T CD4+ and B CD19+ Lymphocytes of Kidney Transplant Recipients

Conditions
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Rejection, Kidney Transplantation

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Kidney transplant recipients with a well functioning graft (serum creatinine ≤ 2,0 mg/dL at inclusion) Must be on tacrolimus therapy Must be on short term follow up time (1 to 5 months) after surgery Exclusion Criteria: A concomitant second solid organ transplant Immunosuppression not containing tacrolimus

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Healthy volunteers<br>Healthy volunteers - subjects without exposure to tacrolimus. Blood samples from these subjects will be used in in vitro experiments. | |
| kidney transplant (KTx) months 1-2<br>Kidney transplant recipients recruited during the months 1 to 2 of follow up after kidney transplantation surgery. These are subjects expected to be exposed to high blood levels of tacrolimus. Blood samples from these subjects will be used in ex vivo experiments. | |
| KTx months 4-5<br>Kidney transplant recipients recruited during the months 4 to 5 of follow up after kidney transplantation surgery. These are subjects expected to be exposed to standard blood levels of tacrolimus. Blood samples from these subjects will be used in ex vivo experiments. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between blood and intracellular levels of tacrolimus | The concentration of tacrolimus will be determined in the whole blood, in T CD4+ cell suspension and in B CD19+ cell suspension prepared from one blood sample per patient subject. The correlations among concentrations of tacrolimus in the 3 different cell matrices will be established. | From 1 up to 5 months post transplantation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation among intracellular levels of tacrolimus and its pharmacological effects | The pharmacological effects of tacrolimus will be measured as the inhibition of the nuclear translocation of NFAT transcription factor, the phosphorylation state of p38 MAP kinase and the production of interleukin 2 and 10 by flow cytometry. | From 1 up to 5 months post transplantation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Tacrolimus, T Lymphocytes, B lymphocytes, Monitoring, Immunologic