Effect of aspirin on beta-receptors in lymphocytes from patients with aspirin-induced asthma.

We studied the effect of aspirin on beta-adrenergic receptors in lymphocytes from three groups of subjects: 5 asthmatic patients presenting sensitivity to aspirin, 10 asthmatic patients with tolerance to aspirin and a control group. Lymphocytes were incubated with aspirin-lysine (36 micrograms/ml). The number of beta-receptors/cell and the dissociation constants (Kd) were assessed by means of [125I]-cyanopindolol (ICYP). There was a decrease in the number of beta-receptors after incubation with aspirin in all asthmatic patients with sensitivity. The differences between mean basal (660 +/- 171 receptors/cell) and postincubation (398 +/- 110 receptors/cell) values were significant (p < 0.05). There were also significant differences (p < 0.01) between basal (23.4 +/- 6 pM) and postincubation (15 +/- 5.1 pM) Kd values, which indicates that the affinity of ICYP increased. In the subjects in the other two groups, aspirin both increased and decreased the number of beta-receptors, but the effects were not significant. It is suggested that in patients with sensitivity, aspirin could induce changes in the plasmatic membrane, thus altering beta-receptors or inducing the release of inflammatory mediators that exert their effect upon these receptors.