Standardized Approach for Monitoring Plasma Cell Disorders

Abstract

Abstract Multi-color flow cytometry using consensus surface markers (CD138, CD38, CD19, CD45, CD27, CD56, CD81, and CD117), intracellular kappa and lambda, as well as other auxiliary markers is routinely used for the identification and characterization of plasma cells. Here, we describe the development of a modular 10-color plasma cell panel for immunophenotyping of the plasma cell compartment. The panel was developed as an 8-color dried backbone, manufactured in a single test-per-tube, ready to use format. The dried backbone can be supplemented with liquid (drop in) reagents, which provides the flexibility of using intracellular kappa and lambda to examine clonality or using CD38-multi-epitope and/or anti-p63 (VS38c) reagent(s). The single test-per-tube format is ideally suited for MRD applications, where sample size is limited and acquisition of millions of events is needed for data analysis. In addition, the dried reagent tubes have a long shelf life (12 months at 20–25°C vs. 24 hours for liquid cocktails with multiple BV dyes in BSB buffer at 2–8°C). Furthermore, utilization of multiple high-performing polymer dyes in the panel affords high resolution of the relevant cell populations. The dried plasma cell tube(s) were tested on bone marrow samples from healthy and diseased subjects in conjunction with intracellular staining for kappa and lambda. Our results demonstrate that the 10-color plasma cell panel can be used for identification of the plasma cell compartment (based CD38 and CD138 expression), assessment of aberrant marker expression (CD19, CD27, CD81, CD117, CD45, and CD56) for the identification of normal and abnormal plasma cells, and examining clonality in multiple patient samples (Kappa and Lambda).