Data_Sheet_1_Ektacytometry Analysis of Post-splenectomy Red Blood Cell Properties Identifies Cell Membrane Stability Test as a Novel Biomarker of Membrane Health in Hereditary Spherocytosis.PDF

Hereditary spherocytosis (HS) is the most common form of hereditary chronic hemolytic anemia. It is caused by mutations in red blood cell (RBC) membrane and cytoskeletal proteins, which compromise membrane integrity, leading to vesiculation. Eventually, this leads to entrapment of poorly deformable spherocytes in the spleen. Splenectomy is a procedure often performed in HS. The clinical benefit results from removing the primary site of destruction, thereby improving RBC survival. But whether changes in RBC properties contribute to the clinical benefit of splenectomy is unknown. In this study we used ektacytometry to investigate the longitudinal effects of splenectomy on RBC properties in five well-characterized HS patients at four different time points and in a case-control cohort of 26 HS patients. Osmotic gradient ektacytometry showed that splenectomy resulted in improved intracellular viscosity (hydration state) whereas total surface area and surface-to-volume ratio remained essentially unchanged. The cell membrane stability test (CMST), which assesses the in vitro response to shear stress, showed that after splenectomy, HS RBCs had partly regained the ability to shed membrane, a property of healthy RBCs, which was confirmed in the case-control cohort. In particular the CMST holds promise as a novel biomarker in HS that reflects RBC membrane health and may be used to asses treatment response in HS.

遗传性球形红细胞增多症（HS）是最常见的遗传性慢性溶血性贫血类型。其病因是红细胞（RBC）膜及细胞骨架蛋白发生突变，破坏红细胞膜完整性并引发膜泡化，最终导致变形性较差的球形红细胞在脾脏内滞留。脾切除术是HS临床常用的治疗手段，其临床获益源于清除红细胞破坏的主要位点，从而改善红细胞存活状态。但红细胞特性的改变是否参与介导脾切除术的临床获益，目前尚不明确。本研究采用红细胞衍射流变检测（ektacytometry）技术，对5名特征明确的HS患者在4个不同时间点，以及由26名HS患者组成的病例对照队列，探究了脾切除术对红细胞特性的纵向影响。渗透梯度红细胞衍射流变检测结果显示，脾切除术后患者红细胞的胞内黏度（水化状态）得到改善，而红细胞总表面积及表面积体积比基本无变化。用于评估体外剪切应力响应的细胞膜稳定性试验（CMST）结果表明，脾切除术后HS患者的红细胞已部分恢复健康红细胞所具备的膜脱落能力，这一发现在病例对照队列中得到验证。尤为关键的是，CMST有望成为反映HS患者红细胞膜健康状态的新型生物标志物，可用于评估HS的治疗响应。