Morphology and density features of eosinophil leukocytes in eosinophilic pneumonia. A case report

We compared the morphological characteristics and density properties of eosinophil leukocytes obtained from the blood and bronchoalveolar lavage fluid of a 29-year-old patient with chronic eosinophil pneumonia during exacerbation. The lavage eosinophils were significantly increased in size when compared with blood cells (surface area: 208 +/- 12 microns 2 versus 161 +/- 13 microns 2). Moreover, eosinophils contained slightly more granules (23.4 versus 20.7 per cell surface area), but no difference was found when the number was corrected for cell size. Electron microscopy revealed a loss of granule contents in eosinophils from both blood and bronchoalveolar lavage. Finally, 61% of the lavage eosinophils were hypodense (with a density less than 1.085 g/ml), whereas 96.3% of the blood cells were normodense. In conclusion, our data demonstrate that in chronic eosinophil pneumonia, eosinophils obtained from bronchoalveolar lavage and blood show differences in both their morphology and density, suggesting that eosinophils during migration into the lung may become activated.