Serum Zinc and Secretory IgA Levels Are Important Factors in Children with Food Allergy

Zinc is an essential nutrient and its deficiency causes malnutrition and results in defects in innate and acquired immune responses. Also, zinc is important for highly proliferating cells, especially in the immune system and influences both innate and acquired immune functions. However, the precise roles and molecular mechanisms of zinc's function in allergic response have not been clarified. On the other hand, the IgA antibody is massively produced in the intestinal Peyer’s patches, and the secretory IgA (sIgA) plays an important role on mucosal immune responses. It is considered that sIgA regulates the cause of allergic reactions. We studied serum zinc levels and sIgA levels in children with food allergies and studied their relationship with allergy symptoms. It is a retrospective study using medical records of infants (from 6 months to 6 years old) who had been admitted to our hospitals. We classified the groups according to the results of physical examinations with or without allergic symptom (eczema, wheezing, food allergy). In addition, we investigated the white blood cell counts (eosinophils and basophils) and the serum levels of specific IgE, total IgA, sIgA, TARC (thymus and activation-regulated chemokine), and zinc. Children who were low levels in sIgA and serum zinc have past histories of atopic dermatitis, and their serum levels of specific IgE was significantly higher (p=0.013) but their serum IgA level was significantly lower (p=0.038) compared with children who does not have allergic symptoms. Secretory IgA levels and zinc levels are also important to the onset of allergic reactions.