Chitotriosidase activity in patients with interstitial lung diseases

BACKGROUND: In previous papers, we found significantly higher activity of chitotriosidase, a macrophage derived enzyme, in serum and BAL of patients with sarcoidosis, especially in those with progressing disease and lung involvement, than in controls. Locally and systemically produced chitotriosidase activity was correlated with radiological stage and also with degree of lung infiltration, suggesting that this enzyme may play a role in the pathogenesis of sarcoidosis and may be used as a marker of disease severity. AIM: To analyse chitotriosidase activity in serum and bronchoalveolar lavage of patients with idiopathic pulmonary fibrosis and pulmonary fibrosis associated with systemic sclerosis and to compare it with chitotriosidase activity in controls and sarcoidosis patients. METHODS: Chitotriosidase activity was determined by a fluorometric assay. RESULTS: The results showed that serum chitotriosidase activity was only elevated in sarcoidosis patients; in patients with idiopathic pulmonary fibrosis and pulmonary fibrosis associated with systemic sclerosis it was in the normal range. On the contrary, in BAL of sarcoidosis and idiopathic pulmonary fibrosis patients the activity was significantly higher than in controls. CONCLUSION: Serum chitotriosidase is a potential marker of sarcoidosis severity; it increases in sarcoidosis in relation to radiological stage and degree of lung infiltration. The increase in chitotriosidase activity in BAL of sarcoidosis and idiopathic pulmonary fibrosis patients suggests that the enzyme could be involved in fibrogenesis in diffuse lung diseases. Further research is needed to understand the role of chitotriosidase in the pathogenesis of sarcoidosis and its involvement in fibrotic remodelling in certain diffuse lung diseases.