Evaluation of iMS-IP assay for the detection and typing of monoclonal immunoglobulins
Yu Chen1, Liangshun You2, Li Zhu2
1Department of Hematology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China; Zhejiang Province Key Laboratory of Hematology Oncology Diagnosis and Treatment, Hangzhou, Zhejiang, China.
Background:
Serum and urine protein electrophoresis have long served as the mainstay for monitoring monoclonal protein (M-protein) levels in assessing treatment response for multiple myeloma (MM). Despite limitations in sensitivity and specificity, these methods remain the primary clinical detection techniques.
Methods:
Leftover serum samples previously analyzed by immunofixation electrophoresis (IFE) were tested using the iMS-IP assay. We evaluated the accuracy, sensitivity, and specificity of the iMS-IP assay and preliminarily assessed its potential utility for minimal residual disease (MRD) monitoring in peripheral blood and distinguishing therapeutic monoclonal antibodies (t-mAbs) within a clinical cohort.
Results:
The iMS-IP assay demonstrated high concordance with IFE for M-protein detection while exhibiting superior sensitivity. It detected IgM M-proteins at levels as low as 0.01 g/L and identified trace M-proteins in sera from patients clinically diagnosed with non-secretory MM. Furthermore, the mass spectrometry-based method correctly identified therapeutic mAbs in 87.5 % (7/8) of cases, significantly outperforming IFE.
Conclusions:
The iMS-IP assay shows potential to replace IFE and advance M-protein screening, diagnosis, and monitoring. Further validation of its clinical sensitivity and specificity is warranted to explore its feasibility for peripheral blood MRD assessment.
