Macdougall I C
Renal Unit, St. Bartholomew's Hospital, London, UK.
Curr Opin Nephrol Hypertens. 1994 Nov;3(6):620-5. doi: 10.1097/00041552-199411000-00010.
Patients receiving erythropoietin therapy require large quantities of iron to keep pace with the demands of the bone marrow during active erythropoiesis. If this iron supply to the marrow is not maintained, the response to erythropoietin is impaired, and indeed iron insufficiency is the most common cause of a poor response to this drug. Iron deficiency may be either absolute, which is defined as a reduction in total body iron stores, or functional, which implies adequate iron stores but a failure to supply available iron to the marrow or a failure in the utilization of this iron in the process of erythropoiesis. The detection of absolute or functional iron deficiency is difficult because there is no absolutely reliable marker of iron status, with the exception of an unequivocally low serum ferritin level. Measurement of serum ferritin and transferrin saturation are the most widely used methods, but both have drawbacks. Monitoring of the percentage of hypochromic erythrocytes in the circulation also seems promising, but the technology is of limited availability, and other methods (eg, monitoring erythrocyte ferritin, free erythrocyte protoporphyrin, and erythrocyte zinc protoporphyrin levels) lack widespread validation. Treatment of iron insufficiency is accomplished by intensifying iron supplementation either orally or intravenously, and in many instances the latter route becomes necessary. The high cost of erythropoietin demands that iron deficiency be screened for on a regular basis and treated to maximize the benefits of this drug.
接受促红细胞生成素治疗的患者在活跃的红细胞生成过程中需要大量铁来满足骨髓的需求。如果骨髓的铁供应得不到维持，对促红细胞生成素的反应就会受损，事实上，铁缺乏是对该药物反应不佳的最常见原因。缺铁可能是绝对的，定义为全身铁储存减少，也可能是功能性的，这意味着铁储存充足，但无法向骨髓供应可用铁或在红细胞生成过程中无法利用这些铁。绝对或功能性铁缺乏的检测很困难，因为除了血清铁蛋白水平明确较低外，没有绝对可靠的铁状态标志物。血清铁蛋白和转铁蛋白饱和度的测量是最广泛使用的方法，但两者都有缺点。监测循环中低色素红细胞的百分比似乎也很有前景，但该技术的可用性有限，其他方法（如监测红细胞铁蛋白、游离红细胞原卟啉和红细胞锌原卟啉水平）缺乏广泛验证。铁缺乏的治疗是通过加强口服或静脉补铁来完成的，在许多情况下，后者的途径变得必要。促红细胞生成素的高成本要求定期筛查铁缺乏并进行治疗，以最大限度地提高该药物的益处。
