Detection of Cryoglobulins with flowcytometry

Several patients with cryoglobulin (CG) associated symptoms are seronegative for CG and other potentially causative biomarkers. We analyzed whether it is possible to detect cryoprecipitates by flow cytometry and whether the sensitivity of their demonstration can be increased as compared to visual inspection
Conclusion:
Flow cytometry is equally specific but much more sensitive in the detection of CG than visual inspection
Notes:
Several patients with cryoglobulin (CG) associated symptoms are seronegative for CG and other potentially causative biomarkers. We analyzed whether it is possible to detect cryoprecipitates by flow cytometry and whether the sensitivity of their demonstration can be increased as compared to visual inspection. Sera from 91 patients with suspected CG associated symptoms and 33 healthy controls were examined for the presence of CG by conventional visual testing and by flow cytometry for small diffracting particles. For calibration purposes we tested lipid micelle dilutions (positive controls) by both methods. The minimum concentrations of lipid micelles to be detected by visual inspection and flow cytometry were 128.5pg/ml and 2.0pg/ml, respectively. Among the 91 patients and 33 controls only one patient serum was positive for CG by conventional testing. This sample was also positive on flow cytometry. In the serum of a patient known to be positive for CG, laser diffracting particles were quantified by flow cytometry after keeping serum at 4°C for 3 days. Of the 91 patients, 14 additional samples displayed cold precipitates which re-dissolved after re-warming during flow cytometry. All fifteen (1 + 14) patients positive for CG on flow cytometry suffered from symptoms usually associated with CG. Some precipitates were labeled with anti IgG and IgM antibodies confirming that the particles detected by flow cytometry contained immunoglobulins. No small diffracting particles were detected in the sera of the 33 healthy controls. Flow cytometry is equally specific but much more sensitive in the detection of CG than visual inspection. Dataset 2-Flow Cytometer Sensitivity: A Quadratic Model

部分伴有冷球蛋白（cryoglobulin, CG）相关症状的患者，其血清中冷球蛋白及其他潜在致病生物标志物均呈血清学阴性。本研究旨在探讨能否通过流式细胞术（flow cytometry）检测冷沉淀物，并对比该方法与目视检查法的检测灵敏度是否可得到提升。
结论：
流式细胞术检测冷球蛋白的特异性与目视检查法相当，但灵敏度显著更高。
备注：
部分伴有冷球蛋白相关症状的患者，其血清中冷球蛋白及其他潜在致病生物标志物均呈血清学阴性。本研究旨在探讨能否通过流式细胞术检测冷沉淀物，并对比该方法与目视检查法的检测灵敏度是否可得到提升。本研究纳入91例疑似冷球蛋白相关症状患者及33例健康对照者，分别采用传统目视检测法及流式细胞术检测其血清中是否存在冷球蛋白及微小衍射颗粒。为进行校准，我们通过两种方法检测了脂质微团稀释液（阳性对照）。目视检测法与流式细胞术所能检测到的脂质微团最低浓度分别为128.5pg/ml与2.0pg/ml。在91例患者与33例对照者中，仅1例患者的血清经传统检测法确认为冷球蛋白阳性，该样本在流式细胞术中同样呈阳性。在1例已知冷球蛋白阳性的患者血清中，将血清置于4℃保存3天后，通过流式细胞术对激光衍射颗粒进行了定量分析。在91例患者中，另有14份样本在流式细胞术中检测到冷沉淀物，且该沉淀物经复温后可重新溶解。经流式细胞术检测为冷球蛋白阳性的15例（1+14）患者，均表现出冷球蛋白相关的典型临床症状。部分沉淀物经抗IgG与抗IgM抗体标记后，证实流式细胞术检测到的颗粒含有免疫球蛋白。33例健康对照者的血清中未检测到任何微小衍射颗粒。流式细胞术检测冷球蛋白的特异性与目视检查法相当，但灵敏度显著更高。数据集2：流式细胞术灵敏度：二次模型