Immune function in pure iron deficiency.

Immunologic studies were performed in ten iron-deficient children, aged 12 to 30 months, before and after iron replacement. Chronic infection, malnutrition, and vitamin deficiency were excluded. Mean hemoglobin levels went from 8.2 +/- 0.2 (SEM) to 12.3 +/- 0.3 g/dL after iron replacement. Mean T-cell percentage increased from 50% +/- 3.0% to 58% +/- 3.7%. Absolute numbers of T cells were unchanged. Three children converted negative in vitro proliferative responses to Candida or tetanus antigen. Mean stimulation indexes increased for Candida (6.8 +/- 1.7 to 17.9 +/- 6.7) and tetanus (19.5 +/- 6.0 to 31.7 +/- 8.5). Nine of 16 delayed hypersensitivity skin tests were positive before and ten of ten were positive after iron therapy. The IgG and IgA levels did not change significantly, but IgM levels decreased from 181 +/- 13 to 128 +/- 5 mg/dL. We conclude that T-cell immunity is slightly impaired in pure iron deficiency and that these subtle defects can be corrected with oral iron replacement.