Abstract：
Several studies have demonstrated the analytical sensitivity of MALDI-TOF mass spectrometry (MALDI-TOF MS) by immunoenrichment for M-protein analysis. We report the results of a novel, low-cost, reagent-based extraction process using acetonitrile (ACN) precipitation to enrich for κ and λ light chains which can be analysed by MALDI-TOF MS.
Institutional Ethics committee approval was obtained. Serum samples from patients with monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma (MM), plasmacytoma, AL amyloidosis and Waldenström macroglobulinemia (WM) underwent ACN precipitation. The images obtained were overlaid on apparently healthy donor serum samples to confirm the presence of M-protein. A sample was considered positive for M-protein if there was a sharp or broad peak within the κ or λ mass/charge (m/z) range: m/z- [M + 2H]2+: 11,550-12,300 Da and λ m/z- [M + 2H]2+: 11,100-11,500 Da. Images were acquired at a m/z range of 10,000-29,000 Da. Corresponding serum protein electrophoresis (SPEP), serum immunofixation electrophoresis (IFE) and serum free light chain (sFLC) assay by nephelometry were performed for all the samples.
Two-hundred-and-two serum samples were included in the study: MM- 184 (91%); AL amyloidosis- 2 (1%); plasmacytoma- 8 (4%); MGUS- 6 (3%) and WM- 2 (1%). All the SPEP positive samples were identified by MALDI-TOF MS. Out of 179 samples positive for M-protein by IFE, MALDI-TOF MS was positive in 176 samples (98%). Compared to IFE, the sensitivity and specificity of M-protein identification by MALDI-TOF MS were 98.3% and 52.2%, respectively.
This study demonstrates the feasibility of qualitatively identifying M-protein without the need for antibody-based immunoenrichment, making the technique cost-effective.
Institutional Ethics committee approval was obtained. Serum samples from patients with monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma (MM), plasmacytoma, AL amyloidosis and Waldenström macroglobulinemia (WM) underwent ACN precipitation. The images obtained were overlaid on apparently healthy donor serum samples to confirm the presence of M-protein. A sample was considered positive for M-protein if there was a sharp or broad peak within the κ or λ mass/charge (m/z) range: m/z- [M + 2H]2+: 11,550-12,300 Da and λ m/z- [M + 2H]2+: 11,100-11,500 Da. Images were acquired at a m/z range of 10,000-29,000 Da. Corresponding serum protein electrophoresis (SPEP), serum immunofixation electrophoresis (IFE) and serum free light chain (sFLC) assay by nephelometry were performed for all the samples.
Two-hundred-and-two serum samples were included in the study: MM- 184 (91%); AL amyloidosis- 2 (1%); plasmacytoma- 8 (4%); MGUS- 6 (3%) and WM- 2 (1%). All the SPEP positive samples were identified by MALDI-TOF MS. Out of 179 samples positive for M-protein by IFE, MALDI-TOF MS was positive in 176 samples (98%). Compared to IFE, the sensitivity and specificity of M-protein identification by MALDI-TOF MS were 98.3% and 52.2%, respectively.
This study demonstrates the feasibility of qualitatively identifying M-protein without the need for antibody-based immunoenrichment, making the technique cost-effective.
摘要：
背景：一些研究已经证明了通过免疫富集进行M蛋白分析的MALDI-TOF质谱（MALDI-TOFMS）的分析灵敏度。我们报道了一部小说的结果，低成本,基于试剂的提取过程，使用乙腈（ACN）沉淀富集κ和λ轻链，可通过MALDI-TOFMS进行分析。
方法：获得了机构伦理委员会的批准。来自未知意义的单克隆丙种球蛋白病（MGUS）患者的血清样本，多发性骨髓瘤（MM），浆细胞瘤,AL淀粉样变性和Waldenström巨球蛋白血症（WM）进行了ACN沉淀。将获得的图像覆盖在明显健康的供体血清样品上以确认M蛋白的存在。如果在κ或λ质量/电荷(m/z)范围内存在尖锐或宽峰:m/z-[M+2H]2+:11,550-12,300Da和λm/z-[M+2H]2+:11,100-11,500Da,则样品被认为是M蛋白阳性。在10,000-29,000Da的m/z范围获取图像。相应的血清蛋白电泳（SPEP），对所有样品进行血清免疫固定电泳（IFE）和无血清轻链（sFLC）比浊法测定。
结果:研究中包括两百零二份血清样品:MM-184(91%);AL淀粉样蛋白-2(1%);浆细胞瘤-8(4%);MGUS-6(3%)和WM-2(1%)。所有SPEP阳性样本均由MALDI-TOFMS鉴定。在通过IFE检测的179份M蛋白阳性样本中，MALDI-TOFMS在176个样品中呈阳性(98%)。与IFE相比，MALDI-TOFMS鉴定M蛋白的敏感性和特异性分别为98.3%和52.2%,分别。
结论：这项研究证明了在不需要基于抗体的免疫富集的情况下定性鉴定M蛋白的可行性，使技术具有成本效益。
方法：获得了机构伦理委员会的批准。来自未知意义的单克隆丙种球蛋白病（MGUS）患者的血清样本，多发性骨髓瘤（MM），浆细胞瘤,AL淀粉样变性和Waldenström巨球蛋白血症（WM）进行了ACN沉淀。将获得的图像覆盖在明显健康的供体血清样品上以确认M蛋白的存在。如果在κ或λ质量/电荷(m/z)范围内存在尖锐或宽峰:m/z-[M+2H]2+:11,550-12,300Da和λm/z-[M+2H]2+:11,100-11,500Da,则样品被认为是M蛋白阳性。在10,000-29,000Da的m/z范围获取图像。相应的血清蛋白电泳（SPEP），对所有样品进行血清免疫固定电泳（IFE）和无血清轻链（sFLC）比浊法测定。
结果:研究中包括两百零二份血清样品:MM-184(91%);AL淀粉样蛋白-2(1%);浆细胞瘤-8(4%);MGUS-6(3%)和WM-2(1%)。所有SPEP阳性样本均由MALDI-TOFMS鉴定。在通过IFE检测的179份M蛋白阳性样本中，MALDI-TOFMS在176个样品中呈阳性(98%)。与IFE相比，MALDI-TOFMS鉴定M蛋白的敏感性和特异性分别为98.3%和52.2%,分别。
结论：这项研究证明了在不需要基于抗体的免疫富集的情况下定性鉴定M蛋白的可行性，使技术具有成本效益。
