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

本文对15例唐氏综合征新生儿骨髓增生异常（TMD）的原始细胞进行了超微结构和超微细胞化学检查。并对其中12例有明确免疫学和临床资料的患者与13例唐氏综合征合并巨核细胞白血病（MKL）患者进行比较，以明确原始细胞的细胞学性质。TMD的原始细胞平均血小板过氧化物酶阳性率与MKL相似。TMD的原始细胞含有α颗粒、髓过氧化物酶阳性颗粒、电子透明颗粒、带膜颗粒、嗜碱性粒细胞样颗粒和带铁蛋白颗粒。唐氏综合征MKL母细胞含有电子透明颗粒、带膜颗粒和少量嗜碱性颗粒，但缺乏α颗粒、MPO阳性颗粒和带铁蛋白颗粒。TMD的母细胞分化为巨核细胞、中性粒细胞、嗜碱性粒细胞和成红细胞，而MKL的母细胞分化为未成熟的巨核细胞、成红细胞和少量嗜碱性粒细胞。这一结果与培养实验结果一致，培养实验表明TMD细胞可分化为多种类型的血细胞。

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.