An increase in hemoglobin, platelets and white blood cells levels by iron chelation as single treatment in multitransfused patients with myelodysplastic syndromes: clinical evidences and possible biological mechanisms

Iron chelation therapy can improve hematopoiesis in myelodysplastic syndromes. Only few studies showed hematologic improvement with deferoxamine, and the erythroid responses were correlated with good compliance to long-term treatment. Indeed, single-case reports and data from clinical trials testing the efficacy of deferasirox reported hematologic improvements with varying rates of response in different lineages. Overall, about 760 myelodysplastic syndrome (MDS) patients with iron overload receiving deferasirox were included in six different studies, and an increase in hemoglobin level was reported to range from 6 to 44.5%, an increase in platelet count from 13 to 61%, and in neutrophil count from 3 to 76%. In all the published studies, hematologic improvements were not related to serum ferritin or to non-total binding iron changes; indeed, other pathways were indicated as possible pathogenetic mechanisms, such as decreased NF-kB activity, modulation of mTOR signalling, and reduced reactive oxygen species. The aims of this review are to provide all available information relating clinical and hematologic changes after chelation therapy and to discuss potential mechanisms involved in such responses.