ALBUTEROL AND NEDOCROMIL SODIUM AFFECT AIRWAY AND LEUKOCYTE RESPONSES TO ALLERGEN

We investigated the effects of inhaled nedocromil sodium and albuterol administered prior to allergen challenge in the late asthmatic response (LAR) and circulating cells in a double-blind placebo-controlled study. An additional control day (no allergen) was included to determine diurnal variation. On the control day no change in airway caliber occurred, but a diurnal increase in the numbers of all circulating leukocytes except basophils was seen. Placebo premedication followed by allergen challenge caused both an early asthmatic response (EAR) and a late asthmatic response (LAR). Following allergen challenge after placebo the diurnal increase in eosinophils at 8 h was abolished, and elevated eosinophil and basophil counts were observed at 24 h. Nedocromil sodium attenuated both the EAR and the LAR, and it restored the eosinophil and basophil responses toward normal. Albuterol abolished the EAR and attenuated the LAR and the 24-h increase in circulating basophils. No changes in lymphocyte subpopulations were seen. We conclude that during the LAR there is entrainment of eosinophils within the lung, with a subsequent bone marrow response increasing peripheral populations of eosinophils and basophils. Nedocromil sodium may act by inhibiting the recruitment of inflammatory cells, particularly eosinophils, possibly by affecting the generation of cytokines and the expression of leukocyte-specific adhesion molecules. Albuterol may have similar actions as shown by an effect on basophils.