Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 15 6 2017 12 30 466 475 EN Ali Talaei Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Jalil Tavakkol Afshari Immunology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Mohammad Reza Fayyazi Bordbar Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Hamidreza Pouryousof Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Farhad Faridhosseini Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Ali Saghebi Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Amir Rezaei Ardani Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Andisheh Talaei Department of Biotechnology, College of Science, University of Tehran, Tehran, Iran Mohsen Tehrani Department of Immunology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran 2015 10 11 2016 04 05 The pathogenesis of Bipolar I Disorder (BP-I) involves immune-mediated mechanisms, especially an imbalance in pro-inflammatory/anti-inflammatory cytokines in plasma or cerebrospinal fluid. Interleukin-1 (IL-1) gene cluster, coding some of these pro-inflammatory cytokines, might play a role in various neuropathologies related to neuron inflammation. The aim of the present study was to investigate the possible role of IL-1 gene cluster polymorphisms in determining the susceptibility to BP-I in Iranian population. 48 patients with BP-I in Mashhad (in north-eastern Iran), diagnosed by two psychiatrists using SCID (structured clinical interview for DSM disorders) were selected through convenient sampling and were compared with 47 healthy controls, voluntarily enrolled in the study. Patients with non-Persian ethnicity, history of immunoallergic disorders, endocrinopathies, neurologic disorders, and substance-induced mood disorders were excluded from both case and control groups. Genotyping of IL-1 gene cluster polymorphisms, including IL-1a-889, IL-1b +3954, IL-1b-511, and IL-1RN (VNTR) were carried out using Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and compared by SPSS using Fisher’s exact and chi-square tests. The frequency of IL-1b-511 CC genotype and C/T allelic frequency were significantly different between BMD patients and healthy controls (p=0.04 and p=0.02, respectively). Among patients, -511 T allele was significantly more frequent in those with a positive history of major depression. Moreover, +3954 T allele was significantly more frequent in early onset BMD patients. The results suggest a positive association between IL-1 gene cluster variation and BP-I. This polymorphism may contribute to genetic vulnerability through its possible role in neuron inflammation. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/365 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/365/678