再生障碍性贫血患者外周血T细胞FasL的表达分析

目的 比较分析再生障碍性贫血(AA)患者T细胞上Fas配体(FasL)的表达及其在胞内外的分布情况，观察AAT细胞胞浆FasL的释放特性及细胞毒作用。方法 以正常人“静息”T细胞和人为诱导活化的T淋巴母细胞为参照，采用免疫荧光标记和流式细胞技术，检测FasL在AAT细胞表面及胞浆中的分布；用体外大剂量PHA-过性刺激的方式诱导T细胞胞浆FasL的释放；以Jurkat细胞为靶向，同时辅以单抗阻断及超速离心的方法，观察AAT细胞FasL的释放特性和杀伤效应。结果 AA T细胞表面及胞浆中均有FasL的异常表达，其中胞浆FasL的异常表达尤为显著；高浓度胞浆FasL可在大剂量PHA-过性刺激时迅速向胞外释放；PHA刺激后的AAT细胞培养上清有明显的Jutkat细胞杀伤活性，该效应可被FasL McAb阻断，或经超速离心加以去除。结论 AAT细胞是一种处于预活化状态的细胞，具有与T淋巴母细胞相似的活化特征，含有高浓度、能以细胞外体形式诱导释放、具备完整活性的胞浆FasL是其异常活化的一大特点。

Expression pattern of Fas ligand on peripheral T lymphocytes from aplastic anemia patients

Objective To investigate, under the circumstance of aplastic anemia (AA), T cell Fas ligand (FasL) distribution pattern, releasing manner and cytotoxic activity. Methods Using high-dose PHA pulse-stimulation, specific McAb blocking, ultracentrifugation, Jurkat cells cytotoxicity assay and flow cytometric (FCM) analysis, T cells of 8 patients with AA are studied for their FasL expression, release and cytotoxicity, comparing with normal resting T cells and activated T cell blasts. Results The FCM analysis showed that AA T cells abnormally expressed low levels of membrane-bound FasL and contained high levels of intracellular FasL which could be triggered to release by high-dose PHA pulse-stimulation. The supernatants from the PHA-stimulated AA T cells had apparent cytotoxicities on Jurkat cells, which was significantly inhibited by FasL McAb and almost completely removed by ultracentrifugation. Conclusion T cells in patients with AA show characteristics of abnormal activation, which are quite similar to those of T cell blasts and have higher potential of being stimulated to release intracellular FasL in bioactive form of exosomes.