Effect of confounding factors on a phospho-flow assay of ribosomal S6 protein for therapeutic drug monitoring of the mTOR-inhibitor everolimus in heart transplanted patients
Article
Dieterlen, Maja-Theresa, John, Katja, Haase, Susanne, Garbade, Jens, Tarnok, Attila, Mohr, Friedrich W., Bittner, Hartmuth B., Barten, Markus J.
funding text
The present work was funded by the endowed professorship of Prof. Dr. med. Hartmuth B. Bittner for Experimental and Clinical Thoracic Organ Transplantation of the Heart Center Leipzig, GmbH (Leipzig, Germany) and the medical faculty, University of Leipzig (Leipzig, Germany).
abstract
Context: Several assays of monitoring immune cell function have been developed to enhance therapeutic drug monitoring. Objective: An in vitro-validated whole-blood assay of phosphorylated ribosomal protein S6 (pS6RP) was evaluated for confounders to monitor the mTOR-inhibitor everolimus (ERL). Materials and methods: Whole blood samples from 87 heart transplant recipients were analyzed for pS6RP-expression in CD3-positive T-cells by phospho-flow analysis. Results: ERL blood concentration, laboratory parameters, co-medications, demographic and clinical data were reviewed. Conclusion: Evaluating the pS6RP-assay revealed that pS6RP is influenced by cyclosporine A (CsA) blood concentration, duration of ERL treatment, co-medication with thiazide diuretics and different metabolic parameters.