Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 17 2 2018 04 28 188 200 EN Laleh Sharifi Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran AND Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran Asghar Aghamohammadi Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran Nima Rezaei Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran AND Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Sheffield, UK AND Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Reza Yazdani Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran Mahdi Mahmoudi Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran Mohammad Mehdi Amiri Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Farimah Masoumi Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Saied Bokaie Department of Epidemiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Parsova Tavasolian Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Rouzbeh Sanaei Department of Immunology, Iran University of Medical Science, Tehran, Iran Mona Moshiri Department of Microbiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Naeimeh Tavakolinia Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran Tina Alinia Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran Gholamreza Azizi Non-communicable Diseases Research Center, Alborz University of Medical Sciences, Karaj, Iran Abbas Mirshafiey Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran AND Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 2017 04 23 2017 06 11 Common variable immunodeficiency (CVID) is the most common clinical primary antibody deficiency, characterized by increased susceptibility to recurrent bacterial infections. Since Toll-like receptors (TLRs) play an important role in the maturation and differentiation of B-cells, TLRs’ defect can be involved in the pathogenesis of CVID. Therefore, we evaluated the expression of TLR2 and TLR4 and their signaling pathway; also their association with autoimmunity, B-cell subtypes and response to pneumovax-23 were assessed in CVID patients. Sixteen CVID patients were enrolled in the study. Flow cytometry was used for assessing the protein expression of TLR2 and TLR4, and real-time PCR was used for gene expression of myeloid differentiation primary response 88 (MyD88) and toll interacting protein (Tollip). We found a higher protein expression of TLR2 in CVID patients which was associated with lower number of end stage B-cells and hyporesponse to pneumovax-23 vaccination. We showed a lower mRNA expression of MyD88 and an almost equal Tollip mRNA expression in CVID patients compared with controls. There was a profound association between MyD88 gene expression and autoimmunity in CVID patients. According to the presence of the lower number of end stage B-cells and poor vaccine response in CVID patients and their correlation with the higher expression of TLR2, we hypothesized that there is a functional defect in this receptor and/or its downstream in the peripheral blood mononuclear cells (PBMCs) of CVID patients. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/1425 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/1425/815