Вивчено показники Т-клітинної ланки імунітету в осіб віком 19 - 20 років, які з народження проживали на територіях, забруднених радіонуклідами. У цьому випадку вираженої динаміки показників абсолютного числа Т-лімфоцитів у мешканців територій посиленого радіоекологічного контролю, яка підтверджувалася б статистично, у період з 1995 до 2010 рр., не відзначено. Відносні показники Т-лімфоцитів із фенотипами CD3+ і CD4+, а також імунорегуляторний індекс CD4+/CD8+ показали тенденцію до повільного відновлення.

Recently we have shown that rhythmic daily fluctuations of the human blood lymphocyte ability to react with sheep erythrocytes (ER activity) persisted in lymphocytes placed in culture under the dark conditions or day-time illumination. If the illumination was switched over to the night-time, the inversion of this circadian rhythm was observed. The results implied that lymphocytic cells contained a self-sustained light-responsive circadian clock. As ER activity is characteristic of two lymphocyte subpopulations in human blood-T cells and large granular lymphocytes (LGL), we now studied the found circadian clock in enriched fractions of these lymphocyte subpopulations, isolated and maintained in culture separately. It was established that although circadian variations of the lymphocyte activity were evident in both cell fractions, the rhythms turned out light-entrainable only in the LGL one. However, when the two lymphocyte subpopulations were grown in a double-chambered vessel which allowed humoral exchange between them, T cell rhythms also became light-responsive, suggesting that a diffusible element of the photoreceptive/circadian system could be transferred from LGL onto T lymphocytes through a half-permeable membrane. The findings are discussed in the context of an apparent key role of the LGL in the proposed mechanism of non-visual circadian photoregulation in man.