The immune response in iron-deficient children: Impaired cellular defense mechanisms with altered humoral components.

Humoral and cellular defense mechanisms were evaluated in 20 children with iron deficiency anemia and in seven with latent iron deficiency. Serum immunoglobulin concentrations, salivary IgA, and total hemolytic complement were within normal range; C'3 concentration was increased. Tests of lymphocyte function showed impaired delayed hypersensitivity skin responses in vivo and decreased in vitro H-3-thymidine incorporation following stimulation with phytohemagglutinin and candida antigen. Tests of neutrophil function showed normal nitroblue tetrazolium dye reduction, decreased bactericidal function, and increased chemotactic activity. These abnormalities could be detected in latent iron deficiency before the development of clinical anemia suggesting that altered immunologic function was an early manifestation of iron deficiency. Normal results were obtained two to three months after iron therapy was begun. The clinical implication of these findings is disucssed in relationship to the reported susceptibility of iron-deficient children to intercurrent infections.