Soluble CD40 ligand and soluble P-selectin in allergic asthma patients during exercise-induced bronchoconstriction

The interactions between CD40 and its ligand, CD40L, control humoral and cell-mediated immune responses. CD40 ligation may promote asthma-associated inflammatory responses in the airways. Many reports confirm the inflammatory basis of exercise-induced bronchoconstriction (EIB) in asthmatics.

The study was conducted in a group of 19 asthmatic patients (11 with EIB, 8 without EIB) and 8 healthy volunteers. We analyzed the changes in plasma concentrations of soluble CD40 ligand (sCD40L) and soluble P-selectin (sP-selectin) induced by intensive exercise. We also studied possible correlations with the results of measurements commonly associated with asthmatic inflammation.

The study revealed statistically significant higher baseline concentrations of sCD40L--but not sP-selectin--in the group of asthmatics with EIB than in those without. In the asthmatic patients with EIB, sCD40L and sP-selectin concentrations increased significantly 30 minutes after exercise and returned to baseline 24 hours after exercise. Baseline concentrations of sCD40L correlated with baseline sP-selectin or fractional exhaled nitric oxide concentration (FE(NO)), an increase in sP-selectin 30 minutes after exercise, and changes in FE(NO) or bronchial hyperresponsiveness 24 hours after exercise. A statistically significant correlation between an increase in sCD40L concentrations 30 minutes after exercise and an increase in FE(NO) 24 hours after exercise or baseline eosinophil cationic protein was observed.

After exercise in the group of allergic asthmatics with EIB, upregulation of CD40L by increased expression of inflammatory molecules and improved sensitivity of CD40-responsive cell types to the effects of proinflammatory cytokines may play an important role in the increased airway inflammation observed after postexercise bronchoconstriction.