Relationship between Airway Reactivity Induced by Methacholine or Ultrasonically Nebulized Distilled Cold Water and BAL Fluid Cellular Constituents in Patients with Sulfur Mustard Gas-Induced Asthma

The objective of this article was to evaluate the relationship between the bronchial reactivity to methacholine and distilled cold water and inflammatory bronchial alveolar lavage (BAL) cells in mustard gas-induced asthma. This was a randomized, crossover clinical study set in a university hospital. The patients were 17 veterans with mustard gas-induced asthma and 17 normal veterans as a control group. Inhalation challenges with ultrasonically nebulized distilled water and methacholine and BAL via bronchoscopy and were performed in all patients and subjects. All patients did sustain a 20% fall in FEV₁ after methacholine, whereas two of them did not with distilled cold water. The patients were sensitive to distilled cold water with a median PD20 of 8.44 ± 6.55 mL and sensitive to methacholine with the median PC20 of 4.88 ± 4.22 mg/mL. Significant correlation was found between PC20 of methacholine and PD20 of distilled cold water (r = −0.74, p = 0.005). The proportion of BAL macrophages was significantly lower in patients with asthma than in the control group (p = 0.001). The proportions of lymphocytes and neutrophils were similar in the two groups. The percentage of eosinophils was higher in BAL fluid from the asthmatics compared with that in BAL fluid from the control group (p < 0.001). The percentage of the BAL eosinophils significantly correlated with both PC20 of methacholine (r = − 0.58, p = 0.01) and PD20 of distilled cold water (r = −0.81, p = 0.002). No relationship between PC20 of methacholine or PD20 of distilled cold water was found for other inflammatory BAL cells. This study showed that in patients with mustard gas-induced asthma, the degree of airway responsiveness to both methacholine and distilled water was associated with the percentage of BAL eosinophils.