Epinephrine-induced changes in the distribution of lymphocyte subsets in peripheral blood of humans.

We have previously demonstrated that mitogen responsiveness of mononuclear cells (MNC) from peripheral blood is reduced after a single injection of epinephrine to human subjects. The purpose of the present study was to characterize the relative distributions of MNC subsets after epinephrine administration using monoclonal antibodies and conventional cell markers. The absolute number of circulating MNC increased 64% within 30 min after injection of epinephrine, and returned to baseline by 2 hr. Analysis of MNC subsets revealed that there were no changes in the relative percentages of total T lymphocytes [T3+ cells, or neuraminidase-treated sheep red blood cell rosettes (EN-rosettes)], B lymphocytes (B1+, or cells with surface-bound immunoglobulin), or monocytes (by morphologic criteria) after epinephrine administration. The percentage of inducer T cells (T4+) declined at 30 and 60 min postinjection. Overall, the percentage of suppressor/cytotoxic T cells (T8+) did not change after injection of epinephrine; however, analysis of individual subjects revealed opposing responses of this subset. The T4:T8 ratio was 2.19 before injection, declined to 1.56 at 60 min, then increased to 3.10 2 hr postinjection. The percentage of natural killer/killer cells (HNK-1+) increased from a baseline of 15.5% before epinephrine injection to 29.6% at 30 min postinjection, then declined to 11.4% at 2 hr. Therefore, the administration of physiologic doses of epinephrine results in changes in the relative proportions of lymphocyte subsets in peripheral blood, in addition to reduced mitogen responsiveness as reported previously.