Chitotriosidase analysis in bronchoalveolar lavage of patients with sarcoidosis.

Background: Sarcoidosis is a systemic granulomatous disease characterised by T-helper cell/macrophage alveolitis. Activated macrophages release mediators, such as cytokines, chemokines, oxygen radicals, and enzymes. In a previous paper we found higher levels of chitotriosidase, a macrophage derived enzyme, in serum of patients with sarcoidosis than in controls. Serum chitotriosidase levels were correlated with sarcoidosis radiological stages. Human chitotriosidase is involved in the pathogenesis of many lysosomal storage disorders and is selectively expressed in chronically activated tissue macrophages.

Methods: In the present study we determined chitotriosidase concentrations in bronchoalveolar lavage of patients with newly diagnosed pulmonary sarcoidosis (divided into two groups according to clinical parameters) and of controls with an ELISA test.

Results: Significantly different chitotriosidase concentrations were found in BAL of patients than controls, especially in patients with progressing disease.

Conclusion: Chitotriosidase but not angiotensin converting enzyme concentrations correlated with sarcoidosis radiological stages, and also with the degree of lung infiltrate seen by CT-scan, suggesting that the former enzyme (detected locally and sistemically) may play a role in the pathogenesis of the disease. Further studies with a greater number of patients are needed to confirm this hypothesis and to determine whether chitotriosidase may be a marker of the severity of sarcoidosis.