Detection of IL-5 and IL-1 receptor antagonist in bronchoalveolar lavage fluid in acute eosinophilic pneumonia.

Background: Acute eosinophilic pneumonia is an idiopathic cause of respiratory failure, characterized by very high numbers of alveolar eosinophils without significant blood eosinophilia.

Objective: The purpose of this study was to determine which cytokines are associated with acute eosinophilic pneumonia.

Methods: Soluble IL-1 type II receptor and the cytokines IL-1 beta, IL-1ra, IL-3, IL-5, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor-alpha were measured in serum and in bronchoalveolar lavage fluid from two patients with acute eosinophilic pneumonia during both acute and convalescent phases.

Results: Compared with patients with adult respiratory distress syndrome, the patients with acute eosinophilic pneumonia had high bronchoalveolar lavage fluid levels of IL-5, IL-1ra, and soluble type II IL-1 receptor but not IL-1 beta, tumor necrosis factor-alpha, IL-3, or granulocyte-macrophage colony-stimulating factor. Bronchoalveolar lavage fluid levels of IL-5 and IL-1ra fell after resolution of symptoms. In the serum of patients with acute eosinophilic pneumonia, IL-5 was not detectable, and IL-1ra was initially high but fell after corticosteroid treatment.

Conclusion: Acute eosinophilic pneumonia is characterized by locally high levels of IL-5, IL-1ra, and soluble type II IL-1 receptor in the alveolar space.