Evaluation of CD229 as a new alternative plasma cell gating marker in the flow cytometric immunophenotyping of monoclonal gammopathies

Background: Daratumumab is an anti-CD38 immunotherapeutic drug that has increasingly been used to treat patients with heavily pre-treated and relapsed/refractory multiple myeloma. In so doing, the detection of CD38 antigen on plasma cells by flow cytometry is impeded. We hypothesized that alternative markers can be used in place or in addition to CD38 when detecting plasma cells post-treated with daratumumab.Methods: A total of 16 alternative markers were tested using 22 bone marrow aspirates from patients with plasma cell neoplasm. The ability of selected markers to discern plasma cells from other hematopoietic cells were evaluated. The stability of tested markers when stored at 4 or 25 C after T = 0, 24, 48, and 72 h was also established. Finally, selected markers were incorporated into a panel used for monitoring multiple myeloma measurable residual disease to test their utility to identify plasma cells in the presence of daratumumab and/or elotuzumab (anti-CD319) drugs.Results: Out of the 16 tested markers, CD319, CD54, CD229, CD317, and p63 were expressed by >90% of the plasma cells. Only CD319, CD54, and CD229 achieved 100% detection sensitivity. Further analysis showed that CD319 was better than CD229 and CD54 at resolving plasma cells from background hematopoietic cells, with CD54 being the worst (resolution metric, mean ± SD: CD319 [2.04 ± 0.86]; CD229 [1.47 ± 0.45]; and CD54 [1.22 ± 0.60]). CD229 was expressed by >90% of T lymphocytes, whereas CD319 was expressed preferentially by the CD8+ T cells and less frequently in CD4+ T cells. Additionally, CD229 was found on >60% of B and NK cells, as well as minor subsets of monocytes and granulocytes. CD319 was expressed on most NK cells and a minor subset of B cells, granulocytes, and monocytes. Even though CD229 and CD319 were expressed by different leukocyte subsets, their expression levels were highest on plasma cells. The expression of CD138 on plasma cells was significantly lower after storage at 4 C, while the expression levels of CD38, CD229, and CD319 remained stable at 4 or 25 C. Using limiting dilution experiments, the treatment of cells with daratumumab severely impeded the detection of CD38 antigen on plasma cells, whereas elotuzumab treatment did not block detection of CD319 on plasma cells.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

CD319 (SLAMF7) an alternative marker for detecting plasma cells in the presence of daratumumab or elotuzumab

Soh

Tario

Hahn

et al. 2020

“…Plasma cells were identified and gated as described previously (Tembhare et al, 2018). The gating strategy employed is represented in Figure 1.…”

Section: Evaluation Of Cd269 Expression In Plasma Cellsmentioning

confidence: 99%

Expression levels and patterns of B‐cell maturation antigen in newly diagnosed and relapsed multiple myeloma patients from Indian subcontinent

Sriram

Kunjachan

Khanka

et al. 2022

Self Cite

Background Many novel therapies are being evaluated for the treatment of Multiple myeloma (MM). The cell‐surface protein B‐cell maturation antigen (BCMA, CD269) has recently emerged as a promising target for CAR‐T cell and monoclonal‐antibody therapies in MM. However, the knowledge of the BCMA expression‐pattern in myeloma patients from the Indian subcontinent is still not available. We present an in‐depth study of BCMA expression‐pattern on abnormal plasma cells (aPC) in Indian MM patients. Methods We studied BM samples from 217 MM patients (211‐new and 6‐relapsed) with a median age of 56 years (range, 30–78 years & M:F‐2.29) and 20 control samples. Expression levels/patterns of CD269 (clone‐19f2) were evaluated in aPCs from MM patients and in normal PCs (nPC) from uninvolved staging bone marrow samples (controls) using multicolor flow cytometry (MFC). Expression‐level of CD269 was determined as a ratio of mean fluorescent intensity (MFI‐R) of CD269 in PCs to that of non‐B‐lymphocytes and expression‐pattern (homogenous/heterogeneous) as coefficient‐of‐variation of immunofluorescence (CVIF). Results Median (range) percentage of CD269‐positive abnormal‐PCs in total PCs was 71.6% (0.49–99.29%). The MFI‐R (median, range) of CD269 was significantly higher in aPCs (4.13, 1.12–26.88) than nPCs (3.33, 1.23–12.87), p < .0001. Median (range) MFI of CD269 at diagnosis and relapse were 2.39 (0.77–9.57) and 2.66 (2.15–3.23) respectively. CD269 levels were similar at diagnosis and relapse, p = .5529. Conclusions We demonstrated that BCMA/CD269 is highly expressed in aPCs from a majority of MM patients, both at diagnosis and relapse. Thus, BCMA is a valuable target for therapy for Indian MM patients.

“…To round out this section on myeloma, Prashant Tembhare and his colleagues from the Tata Memorial Center in Mumbai performed an extensive evaluation of CD229 as an alternate plasma cell gating marker in their manuscript entitled, “ Evaluation of CD229 as a new alternative plasma cell gating marker in the flow cytometric immunophenotyping of monoclonal gammopathies.” All of the strategies recommended for phenotyping plasma cells typically use CD38 and CD138 as gating parameters, however with the advent of antibody‐based therapies such as daratumumab which targets and blocks CD38 and therapies on the horizon to target CD138 alternative gating markers are required. CD138 is further compromised due to loss during sample storage and processing.…”

Section: Multiple Myelomamentioning

confidence: 99%

Issue Highlights—May 2018 (94B3)

Wallace

2018