Effect of TAS2R20 gene polymorphisms on the development of asthma and the course of the disease

Introduction. It is known that bitter taste receptors (TAS2R) are localized in many organs and tissues including the respiratory tract. The functional characteristics of some TAS2R indicate their significant impact on the activity of mucociliary transport, cytokine production, and smooth muscle tone. Thus, TAS2R are often considered as promising targets for the therapy of asthma. Aim. To determine the effect of TAS2R20 polymorphisms on the development of asthma and the characteristics of the disease course. Materials and methods. The study included 230 patients with asthma of varying severity and 208 relatively healthy volunteers. Asthma control was determined using the Asthma Control Questionnaire and lung function were measured by spirometry. Single nucleotide polymorphisms (SNPs) TAS2R20 rs79420812, rs10845281, and rs61912291 were genotyped by PCR with melting analysis of oligonucleotide probes or amplification products. Total immunoglobulin E (IgE) levels in serum were determined using enzyme immunoassay. Results. Carriage of the TT genotype for rs61912291 was associated with uncontrolled asthma after adjustment for gender, age, and smoking status (OR 2.6, 95%CI (1.30-5.07), p=0.007). The same genotype was associated with signs of bronchial obstruction: a decrease in FEV 1 to less than 80% (OR 5.42, 95%CI (1.48-19.87), p=0.01) and FEV 1 /FVC to less than 70% (OR 2.44, 95%CI (1.43-4.18), p=0.001) after adjustment for gender, age, and smoking status. In addition, the homozygous state for the T allele for rs61912291 SNP was more common in asthma patients with IgE level of more than 100 IU/ml (OR 2.6 95%CI (1.22-5.54), p=0.01 after adjustment for gender, age and smoking status). Conclusion. SNPs of TAS2R20 do not affect the development of asthma but may be associated with the features of the disease course. Carriage of the TT genotype for rs61912291 SNP adversely affects the control of asthma, airway patency and is accompanied by an increased IgE level.