Harris Adam Dugger, Rout Emily, Avery Anne, Bolte Denise, Belling-Kelly Erica, Moore A Russell
Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Science, Colorado State University, Fort Collins, CO, USA.
Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
Vet Clin Pathol. 2019 Oct;48 Suppl 1:78-87. doi: 10.1111/vcp.12766. Epub 2019 Aug 13.
Densitometric quantitation using serum protein electrophoresis (SPE) is used to monitor monoclonal proteins (M-proteins) in human patients but has not been validated in the dog. Serum globulin concentrations, species-specific radial immunodiffusion (RID), and ELISAs are currently used in veterinary medicine.
We aimed to compare four methods that quantify M-proteins using densitometry and biuret protein (dM-protein) measurements. We also validated the best performing method and compared it with the RID and ELISA methods for measuring canine serum M-protein.
Serum from six normal dogs and 83 serum samples from 46 dogs with confirmed monoclonal gammopathies were used. A spike and recovery experiment with purified monoclonal IgG and IgM, inter-run and intra-run variability, linearity under dilution, and lower limit of detection were performed. Results of commercial canine RID and ELISA kits for total class-specific immunoglobulin were compared with dM-proteins.
The corrected perpendicular drop gating method had <20% error for IgG/γ-globulin and IgM/β-globulin M-protein quantifications. Linearity (r > .99), intra-run CV (1.1%-2.3%), and inter-run CVs (2.0%-3.5%) were acceptable. Correlation between the RID and densitometry results ranged from r = .25 to r = .88, depending on the class. The RID result was greater than that of the biuret total protein in 26/63 (41%) IgA cases. A panel of IgG, IgA, and IgM RIDs failed to correctly identify an IgM paraproteinemia in 6/6 (100%) cases. Densitometry was not comparable with any other tested method.
Densitometric quantitation is a valid technique for measuring M-proteins in the β- and γ-globulin regions. Immunotyping via RID using the tested kit does not appear to detect IgM. Densitometry is recommended for measuring M-proteins in canine patients.
使用血清蛋白电泳（SPE）进行光密度定量分析用于监测人类患者的单克隆蛋白（M蛋白），但尚未在犬类中得到验证。目前兽医学中使用血清球蛋白浓度、物种特异性放射免疫扩散法（RID）和酶联免疫吸附测定法（ELISA）。
我们旨在比较四种使用光密度测定法和双缩脲蛋白（dM蛋白）测量来定量M蛋白的方法。我们还验证了性能最佳的方法，并将其与测量犬血清M蛋白的RID和ELISA方法进行比较。
使用来自6只正常犬的血清和来自46只确诊单克隆丙种球蛋白病犬的83份血清样本。进行了纯化单克隆IgG和IgM的加样回收实验、批间和批内变异性、稀释线性以及检测下限实验。将商业犬RID和ELISA试剂盒检测总类别特异性免疫球蛋白的结果与dM蛋白进行比较。
校正垂直下降门控法对IgG/γ球蛋白和IgM/β球蛋白M蛋白定量的误差<20%。线性（r>.99）、批内变异系数（1.1%-2.3%）和批间变异系数（2.0%-3.5%）均可接受。RID和光密度测定结果之间的相关性取决于类别，范围从r =.25到r =.88。在26/63（41%）的IgA病例中，RID结果高于双缩脲总蛋白结果。一组IgG、IgA和IgM的RID在6/6（100%）的病例中未能正确识别IgM副蛋白血症。光密度测定法与任何其他测试方法均无可比性。
光密度定量分析是测量β和γ球蛋白区域M蛋白的有效技术。使用测试试剂盒通过RID进行免疫分型似乎无法检测到IgM。建议使用光密度测定法测量犬类患者的M蛋白。
