L-selectin expression affects T-cell circulation following isoproterenol infusion in humans.

beta-Adrenergic receptor agonists have been shown to affect leukocyte migration. This study examined the expression of cellular adhesion molecules on lymphocyte, monocyte, and granulocyte distribution following an infusion of isoproterenol (20 and 40 ng/kg/min for 15 min each) in 12 healthy subjects. Leukocyte populations and adhesion molecule expression were determined via flow cytometry. Isoproterenol led to an expected lymphocytosis and leukocytosis. L-selectin expression varied across leukocytes and influenced cell trafficking in response to isoproterenol. Approximately 60% of CD8+ T-cells expressed L-selectin (CD8+CD62L+) and these cells showed no appreciable response to isoproterenol. In contrast, CD8+CD62L- cells showed a robust increase in number and distribution of approximately 100% over baseline (p's < .001). Across CD4+ T-helpers, L-selectin was expressed on approximately 86% of cells. CD4+CD62L+ cells decreased in number and distribution (p's < .001) with isoproterenol, while CD4+CD62L- cells showed a modest increase (p's < or = .05). In contrast to lymphocytes, nearly all monocytes and granulocytes expressed L-selectin; these cells increased and decreased respectively in response to isoproterenol (p's < or = .05). CD11a (the beta 2-integrin LFA-1) was expressed on > 95% of all leukocytes and these data were thus similar to the overall leukocytosis data. CD54 (ICAM-1) was expressed on approximately 60% of mixed lymphocytes and was unchanged in response to isoproterenol. The findings indicate that L-selectin expression influences T-cell trafficking in response to beta-adrenergic stimulation and help further illuminate catecholamine-mediated sympathetic and immune interactions.