Developmental pharmacodynamics of cyclosporine

Objective: To determine the relationship between human development and in vitro cyclosporine (INN, ciclosporin) pharmacodynamics. Methods: Fifty-six subjects ranging in age from 3 months to 39 years were studied in this prospective laboratory investigation at a university children's hospital and clinical pharmacology laboratory. Peripheral blood monocytes were separated from whole blood and cultured with phytohemagglutinin A (5 mu g/mL) and cyclosporine (0, 6.25, 12.5, 25, 50, 100, 500, 1000, 2500, and 5000 ng/mL). Peripheral blood monocytes cultures were assayed for cell proliferation and supernatant interleukin-2 concentration with use of radionuclide DNA tagging and enzyme-linked immunosorbent assay, respectively. After concentration-effect modeling, summary pharmacodynamic parameters, including the maximal drug effect (E-max) and cyclosporine concentration at which 50% of maximal effect (IC50) and 90% of maximal effect (IC90), were determined. These parameters were compared between four consecutive subject age groups: infants (0-1 years), children (>1-4 years), preadolescents (>4-12 years), and adults (>12 years). Results: The peripheral blood monocytes of the infants showed a twofold lower mean IC50 (peripheral blood monocyte proliferation) and sevenfold lower mean IC90 (interleukin-2 expression) than peripheral blood monocytes from older subjects, The three older age groups were similar with respect to mean IC50 and E-max (peripheral blood monocyte proliferation). Lymphocyte subtype proportions measured in peripheral blood monocytes preparations from each age group were generally similar, The experimental conditions (eg, general anesthesia and cyclosporine solvents) did not affect peripheral blood monocytes proliferation, but the highest experimental cyclosporine concentration (ie, 5000 ng/mL) was associated with decreased peripheral blood monocytes viability. Conclusions: Cyclosporine pharmacodynamics in vitro are related to age, This factor, if neglected, may be a source of iatrogenic risk during pediatric immunosuppressive therapy.