Nutritional immunity: a prospective study of thirty-three patients with acute appendicitis.

During a recent 12-month period, serum iron levels, total iron binding capacities (TIBC), and latent iron binding capacities (LIBC) were studied preoperatively and 72 hrs postoperatively in 33 consecutive patients with pathologically confirmed acute appendicitis. Preoperative serum iron levels were significantly reduced in these patients (mean serum iron 32 micrograms/dl; P less than .0001) compared to established normal values (mean 100 micrograms/dl). LICBs were correspondingly elevated whereas TIBCs and mean hemoglobin values remained within the normal range. The reduced availability of serum iron in response to an acute infectious challenge such as appendicitis supports earlier experimental studies by others which suggest that nutritional immunity participates in host resistance to infection. In this study, the degree of serum iron suppression was directly related to the severity of disease (P less than .01).