Iron deficiency, infections, and immune function: a reassessment.

Many physicians believe that patients with iron deficiency have an increased susceptibility to infections. Data in the literature, however, are contradictory, and in many instances the reports are vulnerable to critical review. Literature available through 1976 was analyzed in an attempt to define possible relationships between infections, immune function, and states of iron imbalance, both iron deficiency and overload. Critical points that must be considered for an accurate interpretation were emphasized. It seems clear that the inflammatory response, when assessed by skin reactivity, is diminished in iron deficiency. The precise molecular defect remains undefined, but the abnormality is detected by several assays measuring cell-mediated immunity. Normal function is usually restored following iron repletion.