Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 13 1 2014 02 15 33 39 EN Leila Mohammadi Amirabad Department of Medical Genetics, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran Ghasem Ahangari Department of Medical Genetics, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran Gholamreza Derakhshan Deilami Department of lung diseases, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran 2015 10 16 Asthma is a chronic inflammatory disorder of the airways. The stress is a factor for asthma which indicates a disorder in the function of communicational mediators of nervous and  immunological systems  such  as  neurotransmitters.  A  study  indicated  that  blood serotonin concentration increases in asthmatic patients. Other study indicates that one kind of the serotonin  receptors, named 5HT3A, on PBMCs causes secretion of series of pro- inflammatory cytokines which play important  roles in allergic asthma disease. Thus, we evaluated the ratio expression level of 5HT3A subtype receptors in asthma. The Peripheral Blood Mononuclear Cells were separated from whole blood of 30 allergic asthmatic patients and 30 normal controls by a gradient density centrifugation technique, then the total cellular RNA was extracted and the cDNA was synthesized. This process was followed by real-time PCR using primer pairs specific for 5-hydroxytryptamine 3A subtype receptor mRNA and beta-actin as internal control. Results  revealed  that  relative  gene  expression  of  5-hydroxytryptamine 3A  subtype receptor  increased significantly in Peripheral Blood Mononuclear  Cells of  patients  with asthma in comparison with normal individuals. To conclude, considering 5-hydroxytryptamine 3A subtype receptor role in accomplishment of asthma symptoms, this increase in its expression may exacerbate the seriousness of asthma disease. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/479 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/479/358