Laboratory of Hematology and Hemostasis, Centre Hospitalier Universitaire Brugmann, Brussels, Belgium.
Thromb Res. 2012 Aug;130(2):259-64. doi: 10.1016/j.thromres.2011.10.016. Epub 2011 Nov 12.
The mechanisms of hypercoagulability in sickle cell disease (SCD) are poorly understood.
We aimed to explore the procoagulant activity of endogenous phospholipids (ePL) in the platelet-free plasma of SCD children.
A factor Xa clotting time (XACT), thrombin generation (TG) and a capture-based assay for the detection of procoagulant microparticles (PMP) were used. Forty three SCD children (35 SS, 6 SC and 2 Sβ+) were evaluated at steady-state and compared to 20 controls. Fourteen patients were also evaluated during vaso-occlusive crisis. TG was performed using 10 pM tissue factor without addition of exogenous phospholipids. A control condition was also performed using 10 pM tissue factor and 4 μM phospholipids. Percentages of the test/control conditions were calculated for the peak height (% peak), endogenous thrombin potential (% ETP) and velocity index (% VI).
XACT times were shorter, PMP levels, peak height and velocity index of thrombin generation were higher in SCD patients than controls. Lag time and ETP were not different between the two groups. % peak, % ETP and % VI were higher in patients than controls. Significant correlations were found between PMP levels and XACT, also between PMP levels and peak height, velocity index, ETP and their respective percentages to the control condition, but not with lag time. Double heterozygous patients showed intermediate values for XACT and TG parameters. No significant difference was observed when comparing patients at steady-state versus vaso-occlusive crisis.
High procoagulant activity of ePL was observed in the platelet-free plasma of SCD children, probably borne by procoagulant microparticles. This may contribute to a high hemostatic potential and predisposition to thrombotic complications in these patients.
镰状细胞病（SCD）患者的高凝机制尚不清楚。
我们旨在探索 SCD 儿童无血小板血浆中内源性磷脂（ePL）的促凝活性。
使用因子 Xa 凝固时间（XACT）、凝血酶生成（TG）和基于捕获的检测促凝微粒（PMP）的方法。稳态时评估了 43 名 SCD 儿童（35 例 SS、6 例 SC 和 2 例 Sβ+），并与 20 名对照进行比较。还在血管阻塞性危象期间评估了 14 例患者。TG 在无外加磷脂的情况下使用 10 pM 组织因子进行。还使用 10 pM 组织因子和 4 μM 磷脂进行了对照条件。计算了测试/对照条件的百分比，包括峰值高度（%峰值）、内源性凝血酶潜能（%ETP）和速度指数（%VI）。
与对照组相比，SCD 患者的 XACT 时间更短，PMP 水平、TG 峰值高度和速度指数更高。两组之间的滞后时间和 ETP 没有差异。与对照组相比，患者的%峰值、%ETP 和%VI 更高。PMP 水平与 XACT 之间以及 PMP 水平与 TG 峰值高度、速度指数、ETP 及其与对照条件的百分比之间存在显著相关性，但与滞后时间无相关性。双重杂合子患者的 XACT 和 TG 参数值处于中间水平。在比较稳态时和血管阻塞性危象时的患者时，未观察到显著差异。
在 SCD 儿童的无血小板血浆中观察到高 ePL 促凝活性，可能由促凝微粒引起。这可能导致这些患者的止血潜能高且易发生血栓并发症。
