Plasma cell myeloma (multiple myeloma [MM]) is a malignant neoplasm originating from the plasma cells. Besides other methods, flow cytometric analysis of the patient's bone marrow aspirate has an important role in the diagnosis and also in the response assessment. Since the cell surface markers, used for identifying abnormal plasma cells, are expressed diversely and the treatment can also alter the phenotype of the plasma cells, there is an increasing demand for new plasma cell markers. VS38c is a monoclonal antibody that recognizes the CLIMP-63 protein in the membrane of the endoplasmic reticulum. CLIMP-63 is known to be expressed at high levels in normal and pathologic plasma cells in the bone marrow, thus VS38c antibody can be used to identify them. Although VS38c staining of plasma cells is reported to be constant and strong even in myeloma, we were wondering whether sample preparation can affect the staining. We have investigated the effect of different permeabilization agents and washing of the cells on the quality of the VS38c staining and found that in many cases the staining is inadequate to identify the plasma cells. We measured the VS38c staining of the bone marrow aspirates of 196 MM patients and observed that almost all cases showed bright staining with VS38c. However, permeabilization with mild detergent resulted in the appearance of a significant VS38c^dim subpopulation, which showed increased sensitivity to mechanical stress (centrifugation). Our results indicate that VS38c^dim MM cells can appear due to the improper permeabilization of the endoplasmic reticulum and this finding raises the possibility of the existence of a plasma cell subpopulation with different membrane properties. The significance of this population is unclear yet, but these cells can be easily missed with VS38c staining and can be lost due to centrifugation-induced lysis during sample preparation.

中文翻译：

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流式细胞术检测浆细胞骨髓瘤中 VS38c 标记的局限性

浆细胞骨髓瘤（多发性骨髓瘤[MM]）是一种起源于浆细胞的恶性肿瘤。除其他方法外，患者骨髓抽吸物的流式细胞仪分析在诊断和反应评估中也具有重要作用。由于用于识别异常浆细胞的细胞表面标志物表达方式多种多样，而且治疗也可以改变浆细胞的表型，因此对新的浆细胞标志物的需求不断增加。VS38c 是一种单克隆抗体，可识别内质网膜中的 CLIMP-63 蛋白。已知 CLIMP-63 在骨髓的正常和病理浆细胞中高水平表达，因此 VS38c 抗体可用于鉴定它们。尽管据报道浆细胞的 VS38c 染色即使在骨髓瘤中也是恒定且强烈的，但我们想知道样品制备是否会影响染色。我们研究了不同透化剂和细胞洗涤对 VS38c 染色质量的影响，发现在许多情况下染色不足以识别浆细胞。我们测量了 196 名 MM 患者的骨髓抽吸物的 VS38c 染色，并观察到几乎所有病例都显示 VS38c 的明亮染色。然而，用温和的去污剂渗透导致显着 VS38c 的出现 我们研究了不同透化剂和细胞洗涤对 VS38c 染色质量的影响，发现在许多情况下染色不足以识别浆细胞。我们测量了 196 名 MM 患者的骨髓抽吸物的 VS38c 染色，并观察到几乎所有病例都显示 VS38c 的明亮染色。然而，用温和的去污剂渗透导致显着 VS38c 的出现 我们研究了不同透化剂和细胞洗涤对 VS38c 染色质量的影响，发现在许多情况下染色不足以识别浆细胞。我们测量了 196 名 MM 患者的骨髓抽吸物的 VS38c 染色，并观察到几乎所有病例都显示 VS38c 的明亮染色。然而，用温和的去污剂渗透导致显着 VS38c 的出现^昏暗的亚群，其对机械应力（离心）的敏感性增加。我们的研究结果表明，VS38c ^dim MM 细胞可能是由于内质网的不适当透化而出现的，这一发现提高了存在具有不同膜特性的浆细胞亚群的可能性。这个群体的重要性尚不清楚，但这些细胞很容易被 VS38c 染色遗漏，并且可能由于样品制备过程中离心诱导的裂解而丢失。