White James G, Nichols William L, Steensma David P
Department of Laboratory Medicine, Pathology and Pediatrics, University of Minnesota School of Medicine, Minneapolis, MN, USA.
Platelets. 2007 Jun;18(4):273-83. doi: 10.1080/09537100601065825.
Various mutations in the X-linked transcription factor, GATA-1, may result in dyserythropoietic anemia, macrothrombocytopenia and/or erythropoietic porphyria. The present study has carried out detailed ultrastructural studies of abnormal platelet morphology in one, previously described family with a GATA-1 G208S mutation. The ultrastructural investigations revealed a large proportion of their circulating platelets were hypogranular macrothrombocytes, resembling cells from patients with the Gray Platelet Syndrome. However, most of their platelets contained some alpha granules and a small number contained as many as are present in normal platelets. GATA-1 platelets from family members also contained tubular inclusions formed from elements of the dense tubular system like those observed in the Medich Giant Platelets Disorder. The unique pathology of the GATA-1 family platelets found in this study involved features never observed previously in normal or abnormal platelets. Many of their cells contained unusual flat, tubular membrane sheets, often in parallel association and differing from all other membrane systems in normal platelets and megakaryocytes. In some macrothrombocytes the unusual membranes appeared to isolate areas of cytoplasm. The sequestered areas were platelets within platelets. On rare occasion there were two platelets within one platelet, or, even more rarely, a platelet within a platelet within a platelet. Another unique feature, probably related to platelets within platelets, was the frequent attachment of non-activated platelets to each other to form macrothrombocytes. GATA-1 platelets within platelets and attached to platelets, as well as giant platelets, suggest that proplatelet formation may be abnormal, or that GATA-1 platelets are unable to pinch off from megakaryocyte proplatelets in a normal manner.
X连锁转录因子GATA-1的各种突变可能导致红细胞生成异常性贫血、大血小板减少症和/或红细胞生成性卟啉症。本研究对一个先前描述的携带GATA-1 G208S突变的家系中异常血小板形态进行了详细的超微结构研究。超微结构研究显示，他们循环中的血小板很大一部分是颗粒减少的大血小板，类似于灰色血小板综合征患者的细胞。然而，他们的大多数血小板含有一些α颗粒，少数血小板含有的α颗粒数量与正常血小板中的一样多。该家系成员的GATA-1血小板还含有由致密管状系统成分形成的管状内含物，类似于在梅迪奇巨大血小板病中观察到的那些。本研究中发现的GATA-1家系血小板的独特病理学特征涉及正常或异常血小板中以前从未观察到的特征。他们的许多细胞含有不寻常的扁平管状膜片，常常平行排列，与正常血小板和巨核细胞中的所有其他膜系统不同。在一些大血小板中，这些不寻常的膜似乎将细胞质区域分隔开来。被隔离的区域是血小板内的血小板。偶尔会有一个血小板内有两个血小板，或者更罕见的是，一个血小板内有一个血小板内又有一个血小板。另一个独特特征，可能与血小板内的血小板有关，是未激活的血小板频繁相互附着形成大血小板。血小板内的GATA-1血小板、附着的血小板以及巨大血小板表明，前血小板的形成可能异常，或者GATA-1血小板无法以正常方式从巨核细胞前血小板上脱离。
