Hyperferremia in immunosuppressed patients with acute nonlymphocytic leukemia and the risk of infection.

Hypothesizing that any effect of an increased serum iron and transferrin saturation on the risk of bacterial infection would be particularly important in immunosuppressed patients, we reexamined the effect of hyperferremia on bacterial growth in vitro and studied the pattern and prevalence of hyperferremia in patients receiving treatment for acute nonlymphocytic leukemia (ANLL). Growth of inocula of Escherichia coli and Staphylococcus aureus was significantly greater (1.3- to 5.8-fold) in fresh or heat-inactivated sera obtained from 10 healthy volunteers 3 hours after oral ingestion of ferrous sulfate (mean +/- SEM transferrin saturation 95% +/- 3%) than before (transferrin saturation 34% +/- 10%). Similarly, in heat-inactivated serum samples obtained from six patients with various malignancies, growth of E. coli was significantly greater (2.3- to 5.5-fold) with the elevated transferrin saturation (97% +/- 3%) present 1 to 7 days after receiving chemotherapy than with the normal transferrin saturation (33% +/- 9%) present before. In a prospective evaluation of serial serum iron studies in 12 patients receiving treatment for ANLL, five patients had normal serum iron concentrations initially, but in each patient the transferrin saturation was elevated after receiving chemotherapy, usually to greater than 90% for greater than 15 days in conjunction with prolonged, profound granulocytopenia and fever.