An outbreak of pulmonary mycosis in respiratory burst-deficient (gp91(phox-/-))Mice with concurrent acidophilic macrophage pneumonia.

An outbreak of pulmonary abscessation due to the common environmental fungus Paecilomyces variotii occurred in a colony of gp91(phox-/-)mice, which lack functional NADPH oxidase, the enzyme complex responsible for generating the respiratory burst in phagocytes. Parenchyma surrounding the abscesses showed intense acidophilic macrophage pneumonia, and similar but much milder lesions were present in each of 24 gp91(phox-/-)mice free from other pulmonary lesions. These findings indicate a high prevalence of acidophilic macrophage pneumonia in gp91(phox-/-)mice, or at least in this particular stock. The presence of this lesion may complicate studies in which phagocyte-dependent pulmonary defence plays a significant role.