KL-6, surfactant protein A and D in bronchoalveolar lavage fluid from patients with pulmonary sarcoidosis

Background. KL-6, and surfactant protein A (SP-A) and surfactant protein D (SP-D) derived from alveolar type II cells and/or bronchiolar epithelia[ ce lls have been reported to be useful markers for interstitial lung diseases. Objective: The aim of this study was to measure the levels of these molecu les in bronchoalveolar lavage fluid (BALF) from patients with pulmonary sar coidosis to investigate their relationship with other markers of inflammato ry activity. Methods: We measured KL-6, SP-A and SP-D levels in BALF from p atients with pulmonary sarcoidosis using an ELISA. Results: KL-6 and SP-D, but not SP-A levels were significantly increased in pulmonary sarcoidosis c ompared with controls. KL-6, SP-A and SPD levels were significantly correla ted with each other. KL-6 and SP-D levels were relatively and significantly correlated with the percentage of lymphocytes in BALF. KL-6, SP-D, but not SP-A levels were significantly correlated with the concentration of albumi n in BALF. There was no significant correlation between KL-6, SP-A, or SPD levels and chest X-ray findings, angiotensin-converting enzyme levels, or C D4/CD8 ratio in BALF. Conclusions: We conclude that KL-6 and SP-D levels in BALF were increased in pulmonary sarcoidosis. Since these markers are spec ifically derived from epithelial cells, it is considered that KL-6 and SP-D levels are reflecting damage or release of these markers from epithelial c ells due to the inflammatory response. Copyright (C) 2001 S. Karger AG, Bas el.