Expression of defensins in the lungs in acute respiratory distress syndrome associated with influenza pneumonia

Abstract

Summary. We investigated paraffin slices of the lungs from 35 people died during the 2009 epidemic of influenza A / H1N1. The exudative stage of acute respiratory distress syndrome (ARDS) was diagnosed in 10 cases, the proliferative stage in 16 and the fibrotic stage in 9 cases. Expression of α–defensins (HNP 1–3) in lung tissue was determined by the immunohistochemistry. The highest HNP 1–3 expression level was found during the exudative stage in neutrophils; it was similar in macrophages and alveolocytes type 2. α–defensins were also expressed by the epithelium of terminal bronchioles. During the proliferative stage, the HNP 1–3 expression in neutrophils remained at the high level, it was increased in alveolocytes type 2 and was unchanged in macrophages. During this stage, HNP 1–3 additionally expressed by immature alveolocytes and squamous metaplasia epithelial cells in the terminal bronchioles. During the fibrotic stage, the HNP 1–3 expression in neutrophils was reduced but remained the highest in comparison with that in the other cells; it did not changed in the alveolocytes type 2 and the macrophages. In this stage, HNP 1–3 also expressed in proliferating fibroblasts.