Several-day rhythmic changes in lymphocyte subpopulation composition and peripheral blood levels of interleukin-2 and...

Several-day rhythmic changes in the lymphocyte subpopulation composition and peripheral blood levels of IL-2 and hydrocortisone were studied in healthy men. The samples were collected daily at 8.00. A 4-day rhythm of hydrocortisone secretion manifested synchronously in different individuals. Rhythmic changes in IL-2 level, T-helper/T-suppressor cytotoxic lymphocyte index, and percentage of NK cells in the peripheral blood related to the hormone levels were detected. Rhythmic changes in these parameters should be taken into consideration when evaluating the hormonal profiles and immunological status of healthy subjects and development of methods for correction of abnormalities.