Annual stability in the levels of lymphocyte subpopulations identified by monoclonal antibodies in blood of healthy individuals

The absolute numbers and percentages of lymphocytes, monocytes, and lymphocyte subpopulations in the blood mononuclear cells were examined monthly in two healthy individuals over a 22-month period. The object of this study was to determine whether the levels of lymphocyte subpopulations identified by monoclonal antibodies, Leu4⁺ (T), Leu3⁺ (helper T), Leu2⁺ (suppressor/cytotoxic T), and Leu7⁺ (natural killer) cells, were stable during the year for healthy donors. The results were analyzed by the cosiner method to estimate the rhythmicity of these subpopulations. The number of lymphocytes varied, showing a moderate circannual rhythm with a peak in early summer, whereas the number of monocytes also varied but its variation did not show a specific rhythm. The absolute numbers of T-lymphocyte subpopulations and Leu3⁺ and Leu2⁺ cells showed a covariation, with a peak in early summer in parallel with the circannual rhythm of total lymphocyte counts. A subpopulation of granular lymphocytes with natural killer function, Leu7⁺ cells, also showed a significant variation during the year. Of particular interest is that Leu3/Leu2 ratios were considerably stable during the year. The two-time point examination of these lymphocyte markers including HB-2⁺ B cells in August and January in 15 normal donors did not show any significant differences, although the mean values were slightly higher in summer. The stability and variability of these lymphocyte markers are displayed graphically and the details of these variations are listed.