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Updated: Jun 13, 2026

Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS
Published on: November 8, 2015
CYP3A5 and ABCB1 polymorphisms influence tacrolimus concentrations in peripheral blood mononuclear cells after renal
Arnaud Capron1, Michel Mourad, Martine De Meyer
1Department of Clinical Chemistry, Cliniques universitaires St Luc, Université Catholique de Louvain, Brussels, Belgium.
Aims:
This prospective study investigated the effect of genetic polymorphisms in a biotransformation enzyme (CYP3A5) and a transporter protein (ABCB1) on tacrolimus (Tac) whole blood concentrations in renal transplantation, and more specifically on peripheral blood mononuclear cell (PBMC) drug concentrations, after renal transplantation.
Materials & Methods:
A total of 96 renal transplant recipients were genotyped for the exon 11 (1199G>A), 21 (3435C>T) and 26 (2677G>T/A) polymorphisms in the ABCB1 gene and for the intron 3 polymorphism in the CYP3A5 gene. Tac blood and PBMC concentrations were determined at day 7 after transplantation and at steady state, and then compared with recipient genotypes.
Results & Conclusion:
The ABCB1 1199G>A, 3435C>T and 2677G>T/A SNPs, appeared to reduce the activity of P-glycoprotein towards Tac, increasing Tac PBMC concentrations. The impact of ABCB1 genetic polymorphisms on Tac blood concentrations was negligible. As increased Tac intracellular concentrations might in turn enhance immunosuppressive status and prevention or rejection, ABCB1 recipient genotyping might be useful to better individualize the Tac immunosuppressive therapy in renal transplantation.
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