Circadian rhythm of T-lymphocyte subsets, cortisol and cyclosporin in kidney-transplanted subjects

The present study deals with the 24-h changes in circulating lymphocyte subpopulations in eight subjects with kidney grafts established for 2 to 5 years and treated with cyclosporin. The control group consisted of ten age-matched clinically healthy subjects. The chronobiological analysis of time series documented that the circadian rhythm of T-lymphocyte subsets is undetectable in transplanted subjects. Cortisol rhythmicity persists, however, suggesting that the abolition of T-cell rhtythmicity is not attributable to a desynchronisation of the adrenal cycle. Even though the therapy was combined with prednisolone, the abrogation of rhythmicity for T-lymphocyte subpopulations seems to be related to the immunosuppressive action of cyclosporin, as the plasma concentrations of the drug show no periodic variations along the 24-h span. Antirejection therapy of kidney-transplanted subjects could be adjusted so that cyclosporin is given at a time that would promote suppression of T-lymphocytes without altering their rhythmic performance.