We have determined the number of beta-adrenoceptors and the isoprenaline-stimulated cAMP generation in lymphocyte subsets. The in vitro beta-adrenergic sensitivity was greatest in Tsuppressor/cytotoxic- and natural killer cells and smallest in Thelper- and B-cells. B lymphocytes appear to have a poor receptor coupling to adenylate cyclase as they have many beta-adrenoceptors but generate only little cAMP in response to isoprenaline. 2. A 7 day treatment of healthy volunteers with terbutaline decreased the number of circulating cells in those lymphocyte subsets with a high in vitro sensitivity to beta-adrenoceptor stimulation (i.e. Tsuppressor/cytotoxic- and natural killer cells) but not in those with a poor in vitro sensitivity (i.e. Thelper- and B-lymphocytes). 3. Similar alterations of circulating lymphocyte subsets were found in patients with congestive heart failure (CHF). These alterations were not related to the aetiology of CHF but to its severity and could be correlated with plasma catecholamine levels. 4. We conclude that prolonged exposure to beta-adrenoceptor agonists or enhanced sympathetic activity can decrease the number of circulating lymphocytes with an increase in the Thelper-/Tsuppressor/cytotoxic-cell ratio.
