V. Godding et al., MECHANISMS OF ACUTE EOSINOPHILIC INFLAMMATION IN A CASE OF ACUTE EOSINOPHILIC PNEUMONIA IN A 14-YEAR-OLD GIRL, Clinical and experimental allergy, 28(4), 1998, pp. 504-509
Background. Acute eosinophilic pneumonia (AEP) is characterized by res
piratory distress, eosinophilic infiltration in the lung, acute onset,
resolution of symptoms with corticosteroids and the absence of relaps
e. Studies to identify the pathophysiology of AEP in adults have demon
strated eosinophil activation in the BAL fluid, and the presence of hi
gh levels of interleukin 5 (IL-5) in the BAL. Objective. To investigat
e the pathophysiology of AEP with pleural effusion in a paediatric pat
ient. Methods. ECP levels in the BAL and pleural fluid was determined
by radioimmunoassay. IL-5 and GM-CSF concentrations in the BAL and ple
ural fluid were measured by Elisa. Immunohistochemistry studies perfor
med on open lung biopsy included a specific ICAM-1 immunostaining and
a ECP specific immunostaining (EG2(+)). Results. High levels of ECP we
re found in the BAL (5 mu g/L) and pleural fluid (750 mu g/L) demonstr
ating eosinophil activation at these sites. Immunohistochemistry illus
trated activated (EG2(+)) eosinophils in the interalveolar septa and a
lveolar space and detected increased expression of ICAM-1 on alveolar
epithelial cells. High levels of IL-5 were measured in the BAL (1334 p
g/mL) and pleural fluid (7014 pg/mL), while elevated concentrations of
GM-CSF (150 pg/mL) were found in the BAL. Conclusion. We conclude tha
t in this paediatric patient with AEP activated eosinophils were prese
nt in the BAL fluid, in the interalveolar septa and in the pleural spa
ce while increased ICAM-1 expression was detected on alveolar epitheli
al cells, contributing, at least partly, for their adhesive interactio
ns. IL-5 and GM-CSF are likely important to the massive eosinophil rec
ruitment and activation in the lung, while IL-5 is probably related to
eosinophil accumulation and activation in the pleural space. Thus, lu
ng generation of eosinophil-active cytokines is central to the pathoph
ysiology of AEP in paediatric patients.