Posted on Authorea 31 Mar 2022 | The copyright holder is the author/funder. All rights reserved. No reuse without permission. | https://doi.org/10.22541/au.164873418.81809643/v1 | This a preprint and has not been peer reviewed. Data may be preliminary. The Importance of Aeroallergen Sensitivity in Children with Cystic Fibrosis ¨ OZGE ATAY 1 , SUNA AS ˙ ILSOY 2 , SEDA ¸ S ˙ IR ˙ IN K ¨ OSE 3 ,G ˙ IZEM ATAKUL 4 , serdar al 5 , ¨ OZGE KANGALLI BOYACIO ˘ GLU 2 , Nevin Uzuner 2 , and Ozkan Karaman 2 1 Dokuz Eyl¨ ul University 2 Dokuz Eylul Universitesi Hastanesi 3 SB ¨ U Ankara Dr Sami Ulus Kadın Do˘ gum ¸ Cocuk Sa˘ glı˘gı ve Hastalıkları E˘ gitim ve Ara¸ stırma Hastanesi 4 Dokuz Eylul Universitesi Tip Fakultesi 5 Dokuz Eylul Universitesi March 31, 2022 Abstract Background: Cystic fibrosis (CF) is an inherited autosomal recessive disorder that causes chronic airway disease. In addition to genetic factors, environmental factors may affects the clinical phenotype of CF. In our study, the presence of aeroallergen sensitivity in our patients with CF and its effects on clinical findings were evaluated. Materials and Methods: Demographic characteristics, clinical and laboratory findings, skin prick test (SPT) results, and Modified Shwachman-Kulczycki (MSK) scores of patients diagnosed with CF followed in the Pediatric Respiratory and Allergy Clinic of Dokuz Eylul University Faculty of Medicine were evaluated. Results: We evaluated 51 patients with CF with a median age of 10 (6-18) years. The mean MSK score of the patients was 72.54±11.50, and the mean predictive value of forced expiratory volume (FEV1) in the first second of 41 patients was 80.43±19.50. According to SPT, aeroallergen sensitivity was detected in 17 (33.3%). The frequency of bacterial colonization and bronchiectasis was higher, MSK scores were lower in AF-sensitive patients (p[?]0.01). However, there was no similar difference in other allergen sensitivities. MSK scores and predictive FEV1 values of 25 (49%) patients with bacterial colonization were significantly lower than those without colonization (p=0.001, p=0.005, respectively). Conclusion: Aeroallergen sensitivity was detected in approximately 1/3 of CF patients. Although it has been emphasized in studies that environmental factors may have an impact on lung functions and clinical conditions in CF, the effect of allergens other than AF sensitivity may be less important compared to other environmental factors such as the presence of bacterial colonization. Keywords: Cystic fibrosis, atopy, children, asthma, Aspergillus fumigatus, Pseudomonas aeruginosa INTRODUCTION Cystic fibrosis (CF) is an autosomal recessive inherited disease that may damage the lungs caused by a mu- tation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. 1 Another prevalent chronic childhood lung disease is asthma. 2 The fact that the clinical manifestations in patients with asthma and CF are similar, may be associated with difficulties in differential diagnosis and treatment. 3-5 It was reported for both the diseases that genetic factors and environmental factors, including infections and allergens, affected the lung function of the patients. 3,6 Relevant studies suggested that, in CF, allergens may invade the respi- ratory epithelium as a result of inflammation due to infections, allergic inflammation may cause the patients predisposed to colonization of pathogens, and CFTR mutations may turn individuals susceptible to atopy. 3,7 The most commonly reported allergen susceptibility among CF patients was associated with mold, and espe- cially Aspergillus fumigatus (AF). AF may induce an allergic reaction, including allergic bronchopulmonary 1