A 45-year-old woman has experienced worsening arthritis of her hands and feet for the past 15 years. On physical examination, there are marked deformities of the hands and feet, with ulnar deviation of the hands and swan-neck deformities of the fingers. Laboratory studies show an elevated level of rheumatoid factor. CBC shows hemoglobin, 11.6 g/dL; hematocrit, 34.8%; MCV, 87 mm3; platelet count, 268,000/ mm3; and WBC count, 6800/ mm3. There is a normal serum haptoglobin level, serum iron concentration of 20 mg/ dL, total iron-binding capacity of 195 mg/dL, percent saturation of 10.2, and serum ferritin concentration of 317 ng/mL. No fibrin split products are detected. The reticulocyte concentration is 1.1%. What is the most likely mechanism underlying this patient's hematologic abnormalities?