Chitotriosidase activity in sarcoidosis and some other pulmonary diseases.

BACKGROUND Patients with sarcoidosis have elevated levels of several markers of inflammation. Particularly high levels have been reported for chitotriosidase. In this study, we evaluate whether determining chitotriosidase in serum would be useful in the diagnosis and clinical management of patients with sarcoidosis. METHODS Patients with newly diagnosed sarcoidosis and patients with asthma, fibrosis, asbestosis, lung cancer or chronic obstructive pulmonary disease (n=190) were recruited from an outpatient department. Individuals with no disease (n=26) served as controls. An X-ray was taken, diffusion capacity was measured and blood samples were taken for analysis of chitotriosidase, soluble receptor for interleukin-2, tumour necrosis factor alpha and angiotensin converting enzyme. In most patients with sarcoidosis, the analyses were done before and after regular treatment with corticosteroids over 6 months. RESULTS Some patients with sarcoidosis had markedly high activities of chitotriosidase, but activities above controls were also found among patients with asbestos, fibrosis and lung cancer. There were significant relationships between chitotriosidase and interleukin-2 receptor and angiotensin-converting enzyme. After treatment, chitotriosidase activity decreased in 52 of 69 patients. CONCLUSIONS The results confirm that chitotriosidase activity is markedly increased in some cases of sarcoidosis. As increased activities are also found in other diseases, chitotriosidase cannot be considered a specific marker of sarcoidosis. In cases of sarcoidosis where high CTO activities are found, this enzyme could serve as a useful marker supporting the diagnosis of sarcoidosis when following the effects of treatment and in surveillance for recurrence of the disease.