Romanian Biotechnological Letters Vol. , No. x, Copyright © 2018 University of Bucharest Printed in Romania. All rights reserved ORIGINAL PAPER Biochemical markers of inflammatory syndrome in chronic rhinosinusitis Received for publication, July, 13, 2018 Accepted, August, 6, 2018 ALINA GABRIELA DUŢU 1 , DIANA VLAD 2 , CRISTINA DRUGAN 1* , ALEXANDRA M. CRĂCIUN 1 , TUDOR C. DRUGAN 3 , FLAVIU TABARAN 4 , SILVIU ALBU 2 1 Department of Medical Biochemistry, “Iuliu Haţieganu” University of Medicine and Pharmacy Cluj-Napoca, Cluj-Napoca, Romania 2 2nd Department of Otolaryngology, “Iuliu Haţieganu” University of Medicine and Pharmacy Cluj-Napoca, Cluj-Napoca, Romania 3 Department of Medical Informatics and Biostatistics, “Iuliu Haţieganu” University of Medicine and Pharmacy Cluj-Napoca, Cluj-Napoca, Romania 4 Department of Anatomic Pathology, University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Romania *Address for correspondence to: cdrugan@umfcluj.ro Abstract Chronic rhinosinusitis (CRS), defined as a persistent inflammation of the nasal and sinus mucosa, affects approximately 10% of the European adult population. Our study focused on the evaluation of serum chitotriosidase (Cht) and 25-hydroxyvitamin D3 (25-OH-D3) as potential biomarkers of CRS- associated inflammation. This cross-sectional, randomized, case-control study included 16 CRS patients and 21 non-smoking controls, investigated for nasal septum deviation. No inflammatory conditions were diagnosed in both investigated groups and no anti-inflammatory treatments were administered for at least 3 weeks prior to serum sampling. Serum Cht activity was significantly increased in CRS patients, compared to the controls (Mann-Whitney U test p=0.030), while 25-OH-D3 levels were significantly decreased in patients, versus controls (Mann-Whitney U test p=0.001). No significant Cht or 25-OH-D3 variations were induced by any of the investigated covariates, such as the coexistence of comorbidities, microbial biofilms or previous corticosteroid treatments. Receiver operating characteristic (ROC) analysis indicated a good discriminating capacity between patients and controls, for both Cht and 25- OH-D3, suggesting their possible utility as non-invasive biomarkers in CRS. Patients with polyps exhibited lower 25-OH-D3 levels, while those with microbial biofilms had higher Cht and lower 25-OH- D3 values than their counterparts, suggesting that biofilms may be an aggravating factor in disease pathogenesis. Keywords: chronic rhinosinusitis, biomarkers, inflammation, chitotriosidase, vitamin D. 1. Introduction Chronic rhinosinusitis (CRS) is a frequent pathological condition exhibiting a strong social impact, in terms of reducing the quality of life and increasing the cost of health care. CRS affects approximately 10% of the European adult population and it is defined as a persistent inflammation of the nasal and sinus mucosa, with a length of at least 12 weeks (FOKKENS & al [1]). Based on the potential existence of nasal polyps, CRS is divided into two large subtypes: with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP). The two categories are further differentiated by the type of inflammation and of tissue remodelling (VAN CROMBRUGGEN & al [2]; VAN BRUAENE & al [3]). CRSsNP is characterised by a predominantly neutrophilic inflammatory infiltrate, associated with Th1 lymphocytes (VAN CROMBRUGGEN & al [2]; VAN ZELE & al [4]). Instead, the eosinophilic infiltrate and tissue remodelling based on fibroblast proliferation, with a Th1/Th2 ratio in favour of Th2