en Epidemiology Original Article <div style="text-align: justify;"><span style="font-size:12px;"><span style="font-family:Arial;"><a name="OLE_LINK26"></a><a name="OLE_LINK25"><strong>Background:</strong></a> A fundamental duty of the immune system is to defend against infectious agents. Significant abnormalities were reported in immune parameters of hypothyroid and hyperthyroid patients. In this study, we aim to assess various quantities of antibodies against the tetanus toxin (anti-TT) in hypothyroid and hyperthyroid patients.&nbsp;<br> <strong>Materials and Methods:</strong> Anti-TT levels were measured in serum samples from 50 hypothyroid patients, 50 hyperthyroid patients, and 50 euthyroid individuals, using the ELISA method. Besides, the minimum protective quantity of anti-TT was considered 0.1 IU/mL.<br> <strong>Results:</strong> Seroprotective rates against tetanus were 100, 80, and 96.0 % in euthyroid, hypothyroid, and hyperthyroid groups with the means of 3.52 &plusmn; 0.31, 1.62 &plusmn; 0.21, and 4.07 &plusmn; 0.32 IU/ml, respectively. Accordingly, hypothyroid patients exhibited lower anti-TT levels and seroprotective rates than the euthyroid group (P < 0.001 and P<0.004, respectively). Besides, in the hypothyroid group, anti-TT quantities and seroprotective rates were lower than those in hyperthyroid individuals (P < 0.001 and P < 0.03, respectively).<br> <strong>Conclusions:</strong> The findings demonstrated lower immunity and higher susceptibility to tetanus in patients with hypothyroidism. However, more studies are needed to be conducted in this field to provide more data to be considered in health programs.</span></span></div> Human,Hypothyroidism,Hyperthyroidism,Antibody,Tetanus Toxin. 134 139 http://johe.rums.ac.ir/browse.php?a_code=A-10-61-3&slc_lang=en&sid=1 Mohammad-Taghi Rezayati 22400319475328460011818 22400319475328460011818 No BSc in Laboratory Sciences, Dept. of Immunology, Medical School, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Rafsanjan University of Medical Sciences Ahmad-Reza Sayadi 22400319475328460011819 22400319475328460011819 No Assistant Prof, Social Determinants of Health Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Rafsanjan University of Medical Sciences Ziba Shaabani ** 22400319475328460011820 22400319475328460011820 No Assistant Prof, Immunology of Infectious Diseases Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Rafsanjan University of Medical Sciences Shokoofeh Moghaddam 22400319475328460011821 22400319475328460011821 No BSc in Laboratory Sciences, Pathobiological Laboratory, Medical School, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Rafsanjan University of Medical Sciences Azam Bagherizdaeh 22400319475328460011822 22400319475328460011822 No BSc in Laboratory Sciences, Pathobiological Laboratory, Medical School, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Rafsanjan University of Medical Sciences Fereshteh Iranmanesh 22400319475328460011823 22400319475328460011823 No BSc in Biology, Dept. of Pathology, Medical School, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Rafsanjan University of Medical Sciences Vahid Ehsani 22400319475328460011824 22400319475328460011824 No MSc in Physiology, Dept. of Physiology, Medical School, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Rafsanjan University of Medical Sciences Fahimeh Mohammadizadeh 22400319475328460011825 22400319475328460011825 No BSc in Laboratory Sciences, Pathobiological Laboratory, Medical School, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Rafsanjan University of Medical Sciences Shima Bazaz 22400319475328460011826 22400319475328460011826 No BSc in Laboratory Sciences, Pathobiological Laboratory, Medical School, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Rafsanjan University of Medical Sciences Abdollah Jafarzadeh jafarzadeh14@yahoo.com 22400319475328460011827 22400319475328460011827 Yes Professor, Dept. of Immunology, Medical School, Rafsanjan University of Medical Sciences, Rafsanjan, Iran & Dept. of Immunology, Medical School, Kerman University of Medical Sciences, Kerman, Iran. Kerman University of Medical Sciences