Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA.
Vet Clin Pathol. 2021 Jun;50(2):240-248. doi: 10.1111/vcp.12993. Epub 2021 Apr 13.
Routine electrophoresis [agarose gel electrophoresis (AGE) and capillary zone electrophoresis (CZE)] and species-specific immunofixation (IF) can be used alone or in combination to detect immunoglobulin paraprotein (M-protein) and diagnose secretory myeloma-related disorders (sMRD).
We aimed to evaluate the performance of AGE, CZE, CZE plus IF (CZE-IF), and AGE plus IF (AGE-IF) for detecting canine serum M-proteins.
One hundred canine cases that had AGE, CZE, and routine IF performed on serum, and where B-cell lineage neoplasia (such as B-cell lymphoma and plasma cell tumors) had been diagnosed or excluded, were evaluated. Routine IF protocols targeted IgG-FC, IgA, and IgM heavy chains and light chains. IgG4 IF and free light chain IF were also performed. B-cell lineage neoplasms with an M-protein detected, using any available method, were classified as sMRD. Datasets from AGE, CZE, IF, CZE-IF, and AGE-IF (electrophoretograms, gel images, and fraction concentrations) were composed and reviewed. The sensitivity, specificity, and Youden's index for M-protein detection were determined for each dataset.
The combination of AGE-IF or CZE-IF was more sensitive (82.9%) than CZE alone (72.0%) or AGE alone (64.6%) and more specific (66.1%, 48.3%, 51.7%, respectively). Immunofixation could be used alone to detect M-proteins (sensitivity 82.9%, specificity 61.9%), but there were technical challenges that complicated the performance and evaluation of the test. Myeloma with free light chains only was found in 5/41 cases of sMRD.
Adding routine IF to routine electrophoresis increases the ability to accurately identify M-proteins; however, there is still room for further diagnostic performance improvements.
常规电泳（琼脂糖凝胶电泳[AGE]和毛细管区带电泳[CZE]）和种特异性免疫固定（IF）可单独或联合使用，以检测免疫球蛋白副蛋白（M 蛋白）并诊断分泌性骨髓瘤相关疾病（sMRD）。
我们旨在评估 AGE、CZE、CZE 加 IF（CZE-IF）和 AGE 加 IF（AGE-IF）检测犬血清 M 蛋白的性能。
评估了 100 例犬血清进行 AGE、CZE 和常规 IF 的病例，其中 B 细胞系肿瘤（如 B 细胞淋巴瘤和浆细胞瘤）已被诊断或排除。常规 IF 方案针对 IgG-FC、IgA 和 IgM 重链和轻链。还进行了 IgG4 IF 和游离轻链 IF。使用任何可用方法检测到 M 蛋白的 B 细胞系肿瘤被归类为 sMRD。AGE、CZE、IF、CZE-IF 和 AGE-IF（电泳图谱、凝胶图像和馏分浓度）的数据集被组成并进行了回顾。确定了每个数据集检测 M 蛋白的敏感性、特异性和 Youden 指数。
AGE-IF 或 CZE-IF 的组合比 CZE 单独（72.0%）或 AGE 单独（64.6%）更敏感（82.9%），特异性更高（分别为 66.1%、48.3%、51.7%）。免疫固定术可单独用于检测 M 蛋白（敏感性 82.9%，特异性 61.9%），但该测试的性能和评估存在技术挑战。在 5/41 例 sMRD 中发现仅存在游离轻链的骨髓瘤。
在常规电泳中添加常规 IF 可提高准确识别 M 蛋白的能力；然而，仍有进一步提高诊断性能的空间。
