Endobronchial Biopsy Tissue Evaluation

Endobronchial biopsy tissue specimens were processed routinely, as described in our previous publications [69 (link)]. The 2 µm paraffin-embedded sections were cut and stained with hematoxylin and eosin. The slides were photographed by a Nikon D5300 camera attached to the Zeiss Axioscope microscope with a 100× oil immersion lens. The images were analyzed by the AnalySIS 3.2 software (Soft Imaging System GmbH, Muenster, Germany). The RBM thickness was measured along the biopsy’s epithelial surface according to the orthogonal intercept method suggested by Ferrando et al. [70 (link)] using arbitrary distance units. For each patient, at least 30 individual RBM measurements were evaluated at intervals of 9.5 µm. The results were expressed as harmonic mean, defined in our previous publication.