Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 15 1 2016 01 31 69 74 EN Elahe Rashidi Immunology, Asthma and Allergy Research Institute, Tehran University of Medical Sciences, Tehran, Iran Mohammad Reza Fazlollahi Immunology, Asthma and Allergy Research Institute, Tehran University of Medical Sciences, Tehran, Iran Sara Zahedifard Department of Pathology, Medical Faculty, Shahid Beheshti University of Medical Sciences, Tehran, Iran Azadeh Talebzadeh Immunology, Asthma and Allergy Research Institute, Tehran University of Medical Sciences, Tehran, Iran Anoshirvan Kazemnejad Department of Biostatistics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran Shiva Saghafi Immunology, Asthma and Allergy Research Institute, Tehran University of Medical Sciences, Tehran, Iran Zahra Pourpak Immunology, Asthma and Allergy Research Institute, Tehran University of Medical Sciences, Tehran, Iran AND Department of Immunology and Allergy, Children Medical Center, Tehran University of Medical Sciences, Tehran, Iran 2015 10 25 2015 11 04 Mannose-binding lectin (MBL) is a protein of innate immune system that is involved in opsonization and complement activation. MBL deficiency is associated with predisposition to infectious diseases; however subnormal levels are also seen in healthy subjects. The aim of this study was to investigate the prevalence and clinical manifestation of MBL deficiency in patients with increased susceptibility to infection. We studied the MBL serum concentration of 104 patients with a history of recurrent and/or severe infections referred to Immunology, Asthma and Allergy Research Institute (IAARI) in order to evaluate the primary immunodeficiency (PID). The distribution of MBL deficiency in these patients and 593 healthy subjects of previous study were analyzed. The frequency of individuals with MBL deficiency was significantly higher in patients with recurrent and/or severe infections (13.5% [14/104]) compared with healthy subjects (4.7% [28/593]; p=0.001; OR 3.1, 95% CI 1.5-6.1). However, in 10.9% (7/64) of patients with recurrent infections without any immunodeficiency background, the MBL deficiency was detected. On the whole, our findings indicate an association between MBL deficiency and increased susceptibility to infections. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/628 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/628/613