Holme S, Heaton A, Kunchuba A, Hartman P
Tidewater Red Cross Blood Services, Eastern Virginia Medical School, Norfolk.
Br J Haematol. 1988 Apr;68(4):431-6. doi: 10.1111/j.1365-2141.1988.tb04231.x.
Patients with immune thrombocytopenia have an increased percentage of microthrombocytes/platelet fragments and megathrombocytes. It has been suggested that increased levels of platelet associated IgG (PA-IgG) found in these patients might be related to the presence of this abnormal platelet size distribution. In this study we used flow cytometry to investigate the distribution of PA-IgG within a population of platelets and, in particular, we examined the relationship between platelet size and PA-IgG determined simultaneously on individual platelets. Platelet samples from 10 normals and 31 thrombocytopenic patients were studied. PA-IgG was estimated using immunofluorescent FITC anti-IgG antibody. Binding of FITC anti-IgG to the platelets was quantitated in the flow cytometer as relative mean fluorescence (RMF) which was calibrated against values (in fg/plt of FITC anti-IgG) obtained by spectrofluorometry after solubilization of the platelets. A high correlation (r = 0.89) was found between flow cytometric RMF value and spectrofluorometric FITC anti-IgG values. The flow cytometric studies showed that platelet samples with abnormally elevated levels of FITC anti-IgG (greater than 1.7 fg/plt) not only have a higher percentage of platelets with elevated FITC anti-IgG, but that these platelets also have increased levels of FITC anti-IgG as compared to platelets from normal samples. Platelet size was measured by the amount of forward light scatter in the flow cytometer. A low but significant correlation (r = 0.33 +/- 0.12) was found between size (FALS) and fluorescent signals in samples with elevated FITC anti-IgG. The contribution of 10% of the smallest platelets by FALS and 10% of the largest platelets by FALS to the total levels of flow cytometer platelet fluorescence in these samples was only 4.4% and 19.4% respectively which was not higher than obtained with samples with normal levels of FITC anti-IgG. In conclusion, this study showed that increased levels of PA-IgG found among thrombocytopenic patients were not confined to any particular size class of platelets.
免疫性血小板减少症患者的微血小板/血小板碎片和巨血小板百分比增加。有人提出，这些患者中发现的血小板相关IgG（PA-IgG）水平升高可能与这种异常的血小板大小分布有关。在本研究中，我们使用流式细胞术研究PA-IgG在血小板群体中的分布，特别是，我们检查了血小板大小与在单个血小板上同时测定的PA-IgG之间的关系。研究了10名正常人和31名血小板减少症患者的血小板样本。使用免疫荧光FITC抗IgG抗体估计PA-IgG。FITC抗IgG与血小板的结合在流式细胞仪中定量为相对平均荧光（RMF），该荧光是根据血小板溶解后通过荧光分光光度法获得的值（以fg/plt的FITC抗IgG计）校准的。发现流式细胞仪RMF值与荧光分光光度法FITC抗IgG值之间具有高度相关性（r = 0.89）。流式细胞术研究表明，FITC抗IgG水平异常升高（大于1.7 fg/plt）的血小板样本不仅具有较高百分比的FITC抗IgG升高的血小板，而且与正常样本的血小板相比，这些血小板的FITC抗IgG水平也升高。通过流式细胞仪中的前向光散射量测量血小板大小。在FITC抗IgG升高的样本中，大小（FALS）与荧光信号之间发现低但显著的相关性（r = 0.33 +/- 0.12）。在这些样本中，按FALS计算最小的10%血小板和最大的10%血小板对流式细胞仪血小板荧光总水平的贡献分别仅为4.4%和19.4%，并不高于FITC抗IgG水平正常的样本。总之，本研究表明，血小板减少症患者中发现的PA-IgG水平升高并不局限于任何特定大小类别的血小板。
