T-cell function monitoring in stable renal transplant patients treated with sirolimus monotherapy

Area of Science:

• Immunology
• Pharmacology
• Transplantation

Background:

• Sirolimus offers lymphocyte-specific immunosuppression with a distinct mechanism and safety profile compared to calcineurin inhibitors.
• Optimizing sirolimus therapy necessitates understanding its pharmacokinetic (exposure) and pharmacodynamic (T-cell effect) properties for personalized dosing.
• Identifying reliable biomarkers is crucial for tailoring sirolimus immunosuppression to individual patient needs.

Purpose of the Study:

• To assess the feasibility and reproducibility of combined pharmacokinetic and pharmacodynamic monitoring in kidney transplant recipients on sirolimus monotherapy.
• To investigate the utility of immunosuppression biomarkers in stable kidney transplant patients receiving sirolimus.
• To establish a basis for personalized sirolimus therapy through biological response evaluation.

Main Methods:

• Fourteen stable kidney transplant recipients on sirolimus monotherapy were enrolled.
• Pharmacokinetic and pharmacodynamic parameters were assessed three times over six months.
• Biomarkers including CD4+ T-cell adenosine triphosphate (ATP) and cytokine production (IL-10, IFN-γ, TGF-β) were measured.

Main Results:

• Median sirolimus concentration was 11.5 ng/mL.
• Treated patients showed significantly lower CD4+ T-cell ATP and IL-10 levels compared to healthy controls.
• Inhibition of T-cell proliferation averaged 60%, while IFN-γ and TGF-β levels were comparable to controls.
• Low ATP and IL-10 concentrations were associated with infection presence.

Conclusions:

• Sequential biomarker measurement in stable kidney transplant recipients on sirolimus monotherapy can gauge the drug's biological impact.
• These biomarkers aid in establishing personalized sirolimus therapy based on individual patient responses.
• This approach supports optimizing immunosuppression and potentially managing infection risk.