SummaryIron deficiency is associated with atopy. Iron deficiency during pregnancy increases the risk of atopic diseases in children, while both allergic children and adults are more likely to have iron deficiency anemia. Immunologically, iron deficiency leads to activation of antigen-presenting cells, promotion of Th2 cells and enables antibody class switch in B cells. In addition, iron deficiency primes mast cells for degranulation, while an increase in their iron content inhibits their degranulation. Many allergens, especially those with lipocalin and lipocalin-like protein structures, are able to bind iron and either deprive or supply this trace element to immune cells. Thus, a local induced iron deficiency will result in immune activation and allergic sensitization. However, lipocalin proteins such as the whey protein β‑lactoglobulin (BLG) can also transport micronutrients into the defense cells (holo-BLG: BLG with micronutrients) and hinder their activation, thereby promoting tolerance and protecting against allergy. Since 2019, several clinical trials have also been conducted in allergic subjects using holo-BLG as a supplementary balanced diet, leading to a reduction in symptom burden. Supplementation with holo-BLG specifically supplied defense cells with micronutrients such as iron and therefore represents a new dietary approach to compensate for functional iron deficiency in allergy sufferers.
Allergic Sensitization to Nickel and Implanted Metal Devices
