Early-phase Neutrophilia in Cigarette Smoke-induced Acute Eosinophilic Pneumonia

Although cigarette smoking is a recognized cause of acute eosinophilic pneumonia (AEP), and an increase in eosinophils in the lung is a common occurrence in AEP, early-phase neutrophilia in AEP is not well understood. We describe three cases of cigarette smoke (menthol type)-induced AEP with neutrophilia in the lungs or blood. Increased in-vitro production of the neutrophil chemoattractant interleukin (IL)-8 by human bronchial epithelial cells (HBECs) was correlated with neutrophilia. We suggest that IL-8 released from HBECs is involved in neutrophilia in the lung in AEP, and is newly recognized as an important factor in the early phase of AEP development.