Iron homeostasis during cystic fibrosis pulmonary exacerbation.

BACKGROUND

Hypoferremia is a marker of disease severity in cystic fibrosis (CF). The effect of systemic antibiotics on iron homeostasis during CF pulmonary exacerbation (CFPE) is unknown. Our central hypotheses were that, by the completion of treatment, serum iron would increase, serum concentrations of interleukin-6 (IL-6) and hepcidin-25, two mediators of hypoferremia, would decrease, and sputum iron would decrease.

METHODS

Blood and sputum samples were collected from 12 subjects with moderate-to-severe CF (median percentage-predicted forced expiratory volume in 1 second (FEV(1) %) = 29%; median weight = 56 kg) within 24 hours of starting and completing a course of systemic antibiotics.

RESULTS

After treatment, subjects showed median FEV(1) % and body weight improvements of 4.5% and 2.0 kg, respectively (p < 0.05). Median serum iron rose by 2.4 μmol/L (p < 0.05), but 75% of patients remained hypoferremic. Median serum IL-6 and hepcidin-25 levels fell by 12.1 pg/mL and 37.5 ng/mL, respectively (p < 0.05). Median serum erythropoietin (EPO) and hemoglobin levels were unaffected by treatment. We observed a trend toward lower sputum iron content after treatment.

CONCLUSIONS

Hypoferremia is a salient characteristic of CFPE that improves with waning inflammation. Despite antibiotic treatment, many patients remain hypoferremic and anemic because of ineffective erythropoiesis.