Chitotriosidase activity in sarcoidosis and some other pulmonary diseases

Our plain-English summary of Chitotriosidase activity in sarcoidosis and some other pulmonary diseases, by M. Tercelj, B. Salobir, S. Simcic, et al (Scandinavian Journal of Clinical and Laboratory Investigation, 2009).

The study

• Authors: M. Tercelj, B. Salobir, S. Simcic, B. Wraber, M. Zupancic, R. Rylander
• Journal: Scandinavian Journal of Clinical and Laboratory Investigation
• Published: 2009;69(5):575-8
• Cited by: 34 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

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.

In plain English

This study, from an outpatient lung clinic in Ljubljana, Slovenia, measured chitotriosidase, an enzyme from activated immune cells, in the blood of 88 patients with newly diagnosed, untreated sarcoidosis, 18 with asbestosis, others with asthma, fibrosis, lung cancer or COPD, and 25 of 26 controls classed as having no disease. Average activity was significantly higher than in controls in sarcoidosis, asbestosis, fibrosis and lung cancer, but not in asthma or COPD. Asbestosis patients had a mean of 245 and median of 63 nmol/h/mL, against a control mean of 33. The sarcoidosis mean was 777, significantly higher than in asbestosis or fibrosis. Among sarcoidosis patients, 18 (21%) had activities above 1000, while 9 of 88 had values in the control range. After six months of corticosteroid treatment, activity fell in 51 of 68 sarcoidosis patients (75%). The authors concluded that chitotriosidase is not a specific marker of sarcoidosis but could be a useful tool for diagnosis and follow-up in patients who have high values. They noted that not all tests could be done on all patients and some groups were small.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Clinical comparison of blood marker levels across patient groups with different lung diseases and a control group, with before-and-after measurements in sarcoidosis patients given about 6 months of corticosteroid treatment
• Who was studied: Outpatients at the Department of Respiratory Diseases and Allergy, University Medical Centre, Ljubljana, Slovenia. Table I lists:
• 88 sarcoidosis patients
• 35 asthma patients
• 21 fibrosis patients
• 18 asbestosis patients (mean age 57.6, 31% female)
• 15 lung cancer patients
• 8 COPD patients
• 26 controls classed as 'no disease', whose symptoms were found to be due to upper respiratory infection or reflux

Table II reports chitotriosidase results for 25 controls and 14 lung cancer patients. Study dates are not given.

• Exposure: The article does not describe any asbestos exposure, fiber type, job or dose; asbestosis appears only as one of the diagnostic groups compared. The quantity measured was serum chitotriosidase activity, alongside soluble IL-2 receptor, angiotensin-converting enzyme and X-ray grading. Sarcoidosis patients received oral prednisolone: 20 to 40 mg/day for 1 month, then 12 to 16 mg on alternate days for the rest of the 6 months.
• Main results:
  • Average chitotriosidase activity was significantly higher than in controls in the sarcoidosis, asbestosis, fibrosis and lung cancer groups.
  • Chitotriosidase activity in nmol/h/mL by group:
• Asbestosis (n=18): mean 245, SD 284, median 63, range 15 to 825
• Controls (n=25): mean 33, median 33, range 2 to 68
• Sarcoidosis (n=88): mean 777, median 629
• Fibrosis: mean 302
• Lung cancer: mean 198
• Asthma: mean 48
• COPD: mean 80
  • Activity in sarcoidosis was significantly higher than in fibrosis or in asbestosis.
  • In the asthma and COPD groups, average activities were not significantly different from those of controls.
  • Among the 88 sarcoidosis patients, 18 (21%) had activities above 1000.
  • Among sarcoidosis patients, 9 of 88 had low values in the range of the controls.
  • In sarcoidosis patients, chitotriosidase activity was related to three other measures:
• X-ray grading (r2 0.404)
• soluble IL-2 receptor levels (r2 0.553)
• angiotensin-converting enzyme levels, less strongly (r2 0.264)
  • After corticosteroid treatment, chitotriosidase activity decreased in 51 of 68 sarcoidosis patients (75%). Mean activity went from 824 before treatment to 378 at 6 months.
  • The authors stated that with 1000 as a cut-off for sarcoidosis, specificity in this material would be 100% but sensitivity only 26%.
• The authors' conclusion: The authors concluded that chitotriosidase is high in fibrosis, asbestosis and other diseases, so it cannot be considered a specific marker for sarcoidosis. They added that it is of little diagnostic use unless the value is very high. In their view, it could be a useful clinical tool for diagnosis and surveillance in patients who have high values at diagnosis, and this should be tested in further clinical trials.
• Limitations the authors state:
  • For technical reasons, not all inflammatory measures could be analysed in all patients initially recruited.
  • Some diagnostic groups had small numbers of patients.

Topics

Medical terms in this study, explained in our Lexicon: Inflammation, Fibrosis, Lung Cancer, Necrosis.

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