Report of the European Myeloma Network on multiparametric flow cytometry in multiple myeloma and related disorders

Abstract

The European Myeloma Network (EMN) organized two flow cytometry workshops. The first aimed to identify specific indications for flow cytometry in patients with monoclonal gammopathies, and consensus technical approaches through a questionnaire-based review of current practice in participating laboratories. The second aimed to resolve outstanding technical issues and develop a consensus approach to analysis of plasma cells. The primary clinical applications identified were: differential diagnosis of neoplastic plasma cell disorders from reactive plasmacytosis; identifying risk of progression in patients with MGUS and detecting minimal residual disease. A range of technical recommendations were identified, including: 1) CD38, CD138 and CD45 should all be included in at least one tube for plasma cell identification and enumeration. The primary gate should be based on CD38 vs. CD138 expression; 2) after treatment, clonality assessment is only likely to be informative when combined with immunophenotype to detect abnormal cells. Flow cytometry is suitable for demonstrating a stringent complete remission; 3) for detection of abnormal plasma cells, a minimal panel should include CD19 and CD56. A preferred panel would also include CD20, CD117, CD28 and CD27; 4) discrepancies between the percentage of plasma cells detected by flow cytometry and morphology are primarily related to sample quality and it is, therefore, important to determine that marrow elements are present in follow-up samples, particularly normal plasma cells in MRD negative cases.

Utility of flow cytometry immunophenotyping in multiple myeloma and other clonal plasma cell‐related disorders

“…are generally obtained using CD38 in combination with CD138 versus CD38 alone for BM PC identification and enumeration (34) but the former may provide an easy way to reproduce gating strategy (10). Measurement of 0.5 to 1 Â 10 5 events corresponding to the whole PB and BM sample cellularity is typically recommended for precise identification of PC and their accurate enumeration, after specific exclusion of platelets and debris is attained.…”

“…Thus, a growing number of studies have applied MFC immunophenotyping to the study of PC disorders. (20,(22)(23)(24) Recently, the European Myeloma Network has reported consensus recommendations about the clinical utility of MFC in MM and other clonal PC-related disorders and how to apply it in routine diagnostic laboratory (10). In this article, we review the clinical utility of MFC analysis of PC in the management of patients with PC-related neoplastic disorders.…”

Efficient transduction of healthy and malignant plasma cells by lentiviral vectors pseudotyped with measles virus glycoproteins

“…Healthy plasmablasts and PCs express both Malignant PCs highly express CD138 and CD38, aberrantly CD56, CD200 or CD117 and did not express CD19 and CD45. 25 Data on Figure 3a show these phenotypic characteristics were not modified by H/F-LV transduction. Indeed GFP þ and GFP À primary malignant PCs from one representative patient displayed similar mean fluorescence intensity for CD138, CD38 and CD200, and lacked CD19 and CD45.…”

Evaluating surface erythropoietin receptor in multiple myeloma

“…Staining events are shown in gated plasma cells, which were identified on the basis of CD45, CD38, CD138, CD19, and CD56 expression. 15 Samples from patients 1 --4 were enriched for CD138 þ cells by magnetic-activated cell sorting before staining. Dead cells were excluded from analysis.…”