Immunocompetence in obesity.

Thirty-eight % of obese children and adolescents showed a variable impairment of cell-mediated immune responses in vivo and in vitro and reduction of intracellular bacterial killing by polymorphonuclear leukocytes. The obese group had a higher incidence of iron deficiency and moderately lower serum zinc concentrations. Levels of serum immunoglobulins, complement components C3 and C4, and numbers of T and B lymphocytes were comparable in the two groups. Serum triglycerides, cholesterol and lipoproteins were normal in all subjects. Immunologic changes correlated with the presence of subclinical deficiencies of iron and zinc. Therapy with these micronutrients for 4 weeks resulted in improvement in immunologic responses.