Serum Chitotriosidase Levels in Patients with Allergic and Non-Allergic Asthma

Since the data did not have a normal distribution (Shapiro-Wilk’s test), statistical differences were detected by the Kruskal-Wallis test (p !0.05. ) Serum concentrations of chitotriosidase were 48.72 8 31 nmol/h/ml in allergic asthmatics, 51.5 8 29 nmol/h/ml in non-allergic asmathics and 21.42 8 11 nmol/h/ml in controls ( fig. 1 ). Significant differences were found between the concentrations of chitotriosidase in asthmatics and controls (p ! 0.05 ). Concentra-tions of chitotriosidase greater than normal values were observed in 60% of allergic and 63% of non-allergic asthmatics. No signifi-cant differences were found between chitotriosidase concentra-tions in allergic and non-allergic patients, although the highest concentrations of chitotriosidase were found in 4 patients with documented allergy to dust and moulds. . a l tj e l ec Tre [8] s tudied serum chitotriosidase activity in vari-ous lung diseases, finding concentrations of chitotriosidase in a small population of asthmatics similar to ours. Unfortunately this study did not divide patients according to their history of allergy or specify whether any groups of patients had higher chitotriosi-dase concentrations. Asthma is a complex inflammatory disorder of the airways characterized by bronchial hyper-reactivity to different stimuli, and its pathogenesis is not always completely clear. Chitinases and chitinase-like proteins have recently been proposed as molecules involved in the pathogenesis of asthma with a possible role as prognostic biomarkers [1–6] . Higher serum concentrations of YKL-40 (chitinase-3-like-1), a ‘mammalian chitinase-like protein’, have been reported [2, 4, 5] in asthma patients and hyper-responsive subjects than in con-trols. The YKL-40 gene has been associated with genetic suscep-tibility to the disease. Acid mammalian chitinase (AMCase) has been studied in animal models of airway inflammation [3] and AMCase gene expression has been investigated in detail in BAL fluid macrophages and epithelial brushing from asthma patients [1, 5] . Another member of the chitinase 1 family not yet studied in detail in asthma is chitotriosidase, an enzyme produced by acti-vated macrophages, structurally similar to YKL-40 but having chitinolytic activity [7, 8] . In the last 5 years our research group has investigated the role of chitotriosidase in the pathogenesis of different inflammatory lung diseases, such as sarcoidosis [9] . Here we analyzed serum concentrations of chitotriosidase in al-lergic and non-allergic asthma patients and in a group of controls to evaluate its potential involvement in the different pathways of inflammation occurring in this disease.Ch itotriosidase concentrations were measured in serum sam-ples from 23 patients with allergic asthma, 19 non-allergic asth-matics and 35 healthy controls by a fluorimetric method (Sigma, St. Louis, Mo., USA). Selected patients with PC20 methacholine less than 8 mg/ml were followed at our centre for almost 5 years. They were divided into allergic and non-allergic groups according to medical history, prick test and RAST test results. All patients performed lung function tests, chest X-ray and total IgE analysis at the time of serum sampling. Statistical analysis was performed using Windows software (2005) Graph Pad Prism version 4.0.