骨髄異形成症候群における Sideroblastogram の臨床的意義に関する検討

Clinical utility of sideroblastogram was evaluated by analyzing the sideroblastogram and other clinical data in 66 patients with myelodysplastic syndrome (MDS) [nine with refractory anemia (RA), 27 with RA with excess blasts (RAEB), 24 with RAEB in transformation (RAEBt), and six with chronic myelomonocytic leukemia (CMMoL)]. The sideroblastogram was constituted based on the classification of erythroblasts according to the numbers of stainable iron granules in their cytoplasm : briefly, type 0 as no granules, type Ⅰas 1～2 granules, type Ⅱas 3～5 granules, type Ⅲ as more than 6 granules. The type Ⅲ dominant sideroblastogram (type Ⅲ predominace) was observed in 73% of the patients with MDS in contrast with type 0～Ⅰ predominance in 100% of the healthy volunteers. Although type Ⅲ predominance appeared distinctly in patients who presented erythroid morphological abnormalities, 50% of the patients without abnormalities also had type Ⅲ predominance. Patients with type Ⅲ predominance had more severe macrocytic anemia compared with other dominant types, but type Ⅲ predominance did not influence the disease prognosis. In two cases the sideroblastogram was normalized at complete remission, and returned to type Ⅲ dominance at recurrence of the disease. The type Ⅲ dominant sideroblastogram reflects the disorders of iron metabolism in erythroblasts, and the normalization of the sideroblastogram indicates the appearance of normal etythropoiesis from the normal clone in marrow. We conclude that the sideroblastogram is useful not only in diagnosing MDS but also in clinical evaluation of the therapeutic effect.

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