Holme S, Sweeney J D, Sawyer S, Elfath M D
American Red Cross, Norfolk, Virginia, USA.
Transfusion. 1997 Jan;37(1):12-7. doi: 10.1046/j.1537-2995.1997.37197176945.x.
Recent studies suggested that platelet activation with surface expression of p-selectin on stored platelets may be related to a loss of viability. At present, there has been no thorough investigation of the extent or significance of p-selectin expression during the collection, processing, and storage of platelet concentrates (PCs) under various conditions.
Platelet surface expression of p-selectin (CD62) was determined on fixed platelet samples using fluorescein-conjugated monoclonal antibodies. Platelet viability was assessed by autologous transfusion of platelets stored for 5 days and labeled with either 51Cr or 111in.
Little (2-10%) platelet expression of p-selectin was found in whole blood and platelet-rich-plasma preparations, whereas PCs showed a substantial increase in p-selectin expression to levels of 20 to 30 percent. Both fresh PCs and those stored for 5 days, obtained with one cell separator (MCS, Haemonetics) showed substantially lower levels of p-selectin expression than PCs from two other cell separators (Spectra, COBE, and CS-3000 with TNX-6, Baxter Healthcare). Exposure of platelets to EDTA, cold, or a pH below 6.2, conditions that are known to result in the loss of viability upon transfusion, produced substantial and irreversible p-selectin expression. PCs with a pH of 6.2 to 6.8 (conditions in which no loss of viability has been demonstrated) also showed pronounced p-selectin expression, which returned to control values after incubation at 37 degrees C in plasma at pH 7.0 to 7.2. With storage under current conditions the in vivo studies (n = 61) demonstrated a rather poor correlation between p-selectin expression and the percentage of recovery (r = -0.25) but a somewhat better correlation with survival (r = -0.42). Better correlations were observed with the extent of shape change, lactate, and hypotonic shock response.
These studies show that p-selectin expression on the platelet surface is a predictor of platelet viability, although the extent of shape change and the hypotonic shock response may be more sensitive.
近期研究表明，储存血小板上p-选择素的表面表达所导致的血小板活化可能与活力丧失有关。目前，尚未对不同条件下血小板浓缩物（PCs）采集、处理和储存过程中p-选择素表达的程度或意义进行全面研究。
使用荧光素偶联单克隆抗体在固定血小板样本上测定p-选择素（CD62）的血小板表面表达。通过自体输注储存5天并用51Cr或111In标记的血小板来评估血小板活力。
在全血和富血小板血浆制剂中发现血小板p-选择素表达很少（2 - 10%），而PCs显示p-选择素表达大幅增加至20%至30%的水平。使用一种血细胞分离机（MCS，Haemonetics）获得的新鲜PCs和储存5天的PCs，其p-选择素表达水平明显低于另外两种血细胞分离机（Spectra、COBE以及配备TNX - 6的CS - 3000，Baxter Healthcare）所制备的PCs。血小板暴露于EDTA、低温或pH低于6.2（已知这些条件会导致输血后活力丧失）会产生大量且不可逆的p-选择素表达。pH为6.2至6.8的PCs（尚未证明在此条件下活力丧失）也显示出明显的p-选择素表达，在pH 7.0至7.2的血浆中于37℃孵育后恢复至对照值。在当前条件下储存，体内研究（n = 61）表明p-选择素表达与回收率百分比之间的相关性较差（r = -0.25），但与存活率的相关性稍好（r = -0.42）。在形状改变程度、乳酸和低渗休克反应方面观察到更好的相关性。
这些研究表明，血小板表面的p-选择素表达是血小板活力的一个预测指标，尽管形状改变程度和低渗休克反应可能更敏感。
