Ultracytochemical characteristics of blasts in abnormal myelopoiesis of Down's syndrome

对15例唐氏综合征新生儿短暂性骨髓增生性疾病（TMD）的胚细胞进行了超微结构和超细胞化学研究。并将其中12例与13例唐氏综合征合并巨核母细胞白血病（megakyoblastic leukemia， MKL）患者进行免疫学和临床资料的比较，以明确母细胞的细胞学性质。TMD胚细胞平均血小板过氧化物酶阳性与MKL相似。TMD胚细胞含有α颗粒、髓过氧化物酶阳性颗粒、电子发光颗粒、膜成分颗粒、嗜碱性颗粒和含铁蛋白颗粒。唐氏综合征MKL胚细胞中含有电子朗讯颗粒、膜成分颗粒和少量嗜碱性细胞颗粒，但缺乏α颗粒、mpo阳性颗粒和含铁蛋白颗粒。在TMD胚中观察到分界膜系统，但在患有唐氏综合征的MKL中没有。这些结果表明，TMD的母细胞分化为巨核细胞、中性粒细胞、嗜碱性细胞和红母细胞，而MKL的母细胞分化为未成熟的巨核细胞、红母细胞和少数嗜碱性细胞。这些结果与培养研究一致，表明TMD细胞分化为各种类型的血细胞。

Ultrastructural and ultracytochemical sturies were performed on blasts from 15 Down's syndrome neonates with transient myeloproliferative disorder (TMD). And 12 of them with precise immunological and clinical data were compared with 13 Down's syndrome patients with megakaryoblastic leukemia (MKL) in order to clarify the cytological nature of the blast cells. Average platelet peroxidase-positivity in blast cells of TMD were similar to those of MKL. Blast cells from TMD contained alpha granules, myeloperoxidase-positive granules, electron lucent granules, granules with membrane components, basophil-like granules and granules with ferritin particles. Blast cells from MKL with down's syndrome contained electron lucent granules, granules with membrane components and a few basophil granules, but lacked alpha granules, MPO-positive granules and granules with ferritin particles. A demarcation membrane system was observed in blasts from TMD, but not in MKL with Down's syndrome.These findings suggest that blast cells in TMD show differentiation to megakaryocytes, neutrophils, basophils, and erythroblasts, while blast cells from MKL show limited differentiation to immature megakaryocytes, erythroblasts and a few basophils. And these results coinside with culture studies which showed differentiation of TMD blasts to various types of blood cells.