Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 12 3 2013 09 15 247 253 EN Serap Duru Dışkapı Yıldırım Beyazıt Education and Research Hospital, Chest Diseases Clinic, Ankara, Turkey Gülbahar Yüce Etlik İhtisas Education and Research Hospital, Chest Diseases Clinic, Ankara, Turkey Sevinc Sarinc Ulasli Afyon Kocatepe University, School of Medicine, Department of Pulmonary Diseases, Afyon, Turkey Melike Erdem Dışkapı Yıldırım Beyazıt Education and Research Hospital, Chest Diseases Clinic, Ankara, Turkey Murat Kizilgün Ankara Pediatrics Hematology and Oncology Hospital, Department of Biochemistry, Ankara, Turkey Fatma Kara Ankara Pediatrics Hematology and Oncology Hospital, Department of Biochemistry, Ankara, Turkey Sadık Ardıc Dışkapı Yıldırım Beyazıt Education and Research Hospital, Chest Diseases Clinic, Ankara, Turkey 2015 10 16 YKL-40 (chitinase-3-like-1) has been introduced as a marker of inflammation in asthma. The aim of this study was to determine the role of YKL-40 in asthma and to evaluate the relationship between YKL-40 and asthma severity. In the study, 60 non-smoker asthma patients without additional diseases (aged between 20-60 years, female: 34) were grouped [Group I: Well controlled asthma patients (n: 30), Group II: Patients during acute exacerbation of asthma (n: 30)]. Healthy non-smoker female individuals were included in Group III (n: 30) as a control group. The level of serum YKL-40 of all groups were determined by ELISA. Also, serum YKL- 40 level was correlated with age, asthma duration in years, body mass index (BMI), forced expiratory volume in first second/ forced vital capacity (FEV1/FVC, %), FEV1 (%), and total IgE levels of asthma patients. Mean serum YKL-40 level was highest in patients during acute exacerbation of asthma (36.36±10.49 ng/ml) while mean serum YKL-40 level was the lowest (13.20±5.60 ng/ml) in the control group. There was a negative significant correlation between the serum YKL-40 levels and  FEV1  (%)  in  patients  during  acute  exacerbation  of  asthma.  There  were no significant correlations between the serum YKL-40 levels and other variables in group II. We found that increased serum YKL-40 levels may be used as a marker for evaluation of asthma severity and genetic polymorphism. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/506 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/506/533