DIAGNOSTIC AND BIOLOGICAL SIGNIFICANCE OF SIDEROBLASTIC ERYTHROPOIESIS IN THE MYELODYSPLASTIC SYNDROMES

We retrospectively reviewed clinical and hematologic features of nine patients with acquired idiopathic sideroblastic anemia (AISA). Seven o f them had ringed sideroblasts (RS) more than 15% of marrow nucleated cells. RS persisted in the marrow even in the remaining two patients w ho had a relatively low marrow erythroblasts despite RS ranging from 1 /4 to half of the marrow erythroid series. However, RS declined in pro portion in another two patients of the nine whose disease progressed t o refractory anemia with excess of blasts (RAEB), although a high prop ortion of RS reappeared in one patient at the time of relapse followin g allogeneic marrow transplantation. A similar decline of RS concomita nt with disease progression was also seen in seven additional patients with RAEB or RAEB in transformation (RAEB-t) with sideroblastic eryth ropoiesis. Cytogenetic abnormalities, although rare initially, became detectable either at the time of disease progression or at the worseni ng of anemia in AISA. These observations suggest that the majority of AISA fall in the category of myelodysplasia, and that a progressive de cline in RS is part of the natural history of myelodysplasia. Closer f ollow-up of the proportion of RS in patients with AISA. is warranted t o better understand its biologic significance. (C) 1998 Elsevier Scien ce Ireland Ltd. All rights reserved.