Opposing circadian rhythms of CD3+, CD4+ and CD3+, CD8+ lymphocyte subpopulations in healthy humans

Lymphocyte subpopulations present circadian variation of some of their subsets and this variation may influence the magnitude and expression of immune responses. The aim of this study was to analyze the dynamics of variation of specific lymphocyte subsets. Lymphocyte subpopulation analyses were performed on blood samples collected every four hours for 24 hours from 15 healthy subjects aged 37–54 years. A clear circadian rhythm was validated for CD8 with acrophase at noon and for CD3 and CD4 with acrophase at night. Specific lymphocyte subsets present different profiles of nyctohemeral changes and this might explain time-related variations of immune responses.