Eosinophilic bronchitis-like lesion as the cause of death in a Macaca mulatta: a first case report

Abstract

Background: Eosinophilic bronchitis is a recently described, relatively benign condition in humans that is characterized by a corticosteroid-responsive chronic cough and sputum eosinophilia without the abnormalities of airway function seen in asthma. The exact cause of this condition is currently unknown, however has been associated with various occupational exposures in humans. It has also been reported to progress to irreversible airway obstruction. This disease has been reported in dogs and horses, but not in non-human primates.

Methods: Gross examination of an otherwise healthy 13-year-old, colony-born Macaca mulatta, which died of severe non-responsive respiratory distress revealed that the lungs were markedly inflated and moist.

Results: Hematoxylin and eosin-stained sections from the lungs contained widespread accumulation of eosinophils, sloughed epithelial cells, and mucus centered around bronchioles and adjacent airways. There was no evidence of mast cell infiltration of peribronchiolar smooth muscle, goblet cell hyperplasia, or basement membrane thickening.

Conclusions: This ruled out recurrent episodes as would be expected in asthma, favoring the diagnosis of an eosinophilic bronchitis-like lesion. We report a first case of eosinophilic bronchitis-like features in a M. mulatta.

Fig. 1

(A) Hematoxylin and eosin (H&E)-stained slide (original magnification, 10×) showing airway-centered inflammation. (B) H&E-stained slide (original magnification, 100×) showing bronchitis with excess mucus within the bronchial lumen. (C) H&E-stained slide (original magnification, 400×) showing eosinophilic infiltrate of bronchial epithelium and subepithelium. Note the lack of increased thickness of the subepithelial collagen layer and no increase in goblet cells. (D) Giemsa-stained slides (original magnification, 100×) showing no increase in the number of airway smooth muscle mast cells. (E) Toluidine blue rhesus case tissue with no mast cell granules recognized (600×). (F) Toluidine blue of control tissue with one mast cell with metachromatic granules in circle (600×).