Probable relationship between increased number of birefringent particles and diffuse interstitial lung diseases

Abstract

ABSTRACT Background and aim: Although there is increasing evidence that inhaled birefringent particles (BPs) cause pulmonary fibrotic reaction, the relationship between BPs and diffuse interstitial lung diseases (DILDs) remains unclear. Methods: We assessed 85 cases of interstitial lung diseases including 50 cases of usual interstitial pneumonia (UIP), 22 cases of nonspecific interstitial pneumonia (NSIP) and 13 cases of bronchiolitis obliterans‐organizing pneumonia (BOOP) and 55 cases of normal lung tissue from control group. BPs were measured and counted by image analyzer under polarizing microscope. Results: The average BP count in all types of interstitial lung disease was 223.60/10 high power fields (HPF), significantly higher than the average of 116.80/10HPFs found in the control group (P= 0.01). Among individual disease entities, UIP showed significantly higher BP count than control (232.80/10HPFs, P= 0.01). Although statistically insignificant, NSIP and BOOP also revealed higher BP counts than the control (192.09/10HPFs and 241.54/10HPFs, respectively). Conclusions: Increased BPs in the lung might be related to the fibrogenic process of interstitial lung diseases.