Epithelial regeneration after diffuse alveolar damage in relation to underlying disease and DAD stage: an autopsy study.

UNLABELLED: This study was conducted to characterize the distribution of epithelial regeneration in lungs with diffuse alveolar damage (DAD) and to ascertain whether epithelial regeneration is associated with the underlying disease and/or DAD stage.

METHODS

Lung specimens obtained at autopsy from 18 patients were studied using p63, PE-10 and Ki-67 immunostaining. The patients were categorized into two groups: patients with acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF; IPF group) and patients without IPF (non-IPF group).

RESULTS

p63-positive cells were mostly observed in the alveolar ducts. No significant difference in the appearance of the p63-positive cells was observed between the IPF and non-IPF groups or between the exudative and the proliferative stages. PE-10-positive cells were observed in the alveoli. The number of PE-10-positive cells was significantly higher during the proliferative stage than during the exudative stage. However, p63-positive cells and PE-10-positive cells appeared at day 6 in the earliest case during the exudative stage and Ki-67-positive cells were observed during the exudative stage.

CONCLUSION

Epithelial regeneration was not associated with the underlying disease. This study revealed that regenerative epithelial cells appeared at day 6 during the exudative stage and that the number of type Ⅱ pneumocytes increased significantly during the proliferative stage.