en Artificial intelligence Original Research Original Research We studied the immune system, especially the chemotactic activity of neutrophils, in ten patients with vitamin D-deficient rickets and compared the results with ten healthy controls of matched age. Among all immune system factors, the chemotactic studies persistantly showed remarkable deficiency in leukocyte mobility, both random motion and migration. When compared with controls, the findings were significant. It was postulated that the increased susceptibility of the patients with vitamin D-deficient rickets to infection is mainly due to defective neutrophil Mobility 29 31 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-524&slc_lang=en&sid=1 A A. FARHOUDI 20031947532846005672 20031947532846005672 Yes Form the Children's Medical Center. Tehran University of Medical Sciences, Tehran. Islamic Republic of lran