Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 14 4 2015 10 20 386 391 EN Ali Mosayebian Department of Immunology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. Mazdak Ganjalikhani-Hakemi Cellular and Molecular Immunology Research Center, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. Rezvan Meshkat Department of Immunology, Faculty of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran. Ramin Ghasemi Department of Immunology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. Hossain Khan-Ahmad Department of Genetics and Molecular Biology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. Morteza Samadi Department of Immunology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran AND Reproductive Immunology Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. 2015 10 18 2015 10 18 The SNP (rs11209026, Arg381Gln, R381Q) in the IL-23 receptor (IL23R) confers protection against multiple inflammatory diseases, representing one of the most significant human genetic polymorphisms in inflammatory diseases. We, therefore, investigated the association between IL-23 R R381Q gene polymorphism and asthma.This case-control study was performed on 209 patients, and 200 healthy controls. Using PCR-RFLP,  the  R381Q  variant  was  screened  in  the  IL-23R  gene  of  the  patients  and controls.Serum IgE levels were measured using ELISA technique. Eosinophil absolute count was done with Sesmex cell counter.Our results indicated that the genotype and allele frequencies of the IL-23R R381Q polymorphism is significantly different between asthmatic patients and control subjects (p<0.001; odd ratio= 0.266; 95%, CI=0.118-0.604. Moreover, the asthmatic patients had higher eosinophil count and total serum IgE levels than controls as expected (p<0.001).The present study suggested that R381Q polymorphism in IL-23 receptor may be a predisposing allele for asthma. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/585 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/585/516