Flow cytometric sensitivity and characteristics of plasma cells in patients with multiple myeloma or its precursor disease: influence of biopsy site and anticoagulation method

Abstract

Flow cytometry has increasing relevance for prognosis in myeloma and precursor disease (monoclonal gammopathy of unknown significance/smoldering myeloma), yet it has been reported that plasma cell enumeration by flow varies depending on the quality of marrow aspirate and field biopsied in patchy disease. We demonstrated increased sensitivity of flow over immunohistochemistry in abnormal-plasma cell detection in monoclonal gammopathy (n = 59)/smoldering myeloma (n = 87). We prospectively evaluated treatment-naïve smoldering myeloma (n = 9)/myeloma (n = 11) patients for the percentage of abnormal plasma cells/total plasma cell compartment, plasma cell viability/infiltration and flow immunophenotype depending on anticoagulant use, biopsy site and pull sequence in uni-and-bilateral bone marrow biopsies and aspirates. We found no statistical difference regarding the percentage of abnormal plasma cells, their immunophenotype or number/distribution in marrow samples even when obtained by different sequence in aspirates, or anticoagulants (p>0.05). Our results show that plasma cell enumeration and immunophenotyping by flow cytometry is consistent under different conditions in these populations.

Biological properties of bone marrow plasma cells influence their recovery in aspirate specimens: impact on classification of plasma cell disorders and potential bias to evaluation of treatment response

“…It is commonly recognized that BMPC are vastly underrepresented by flow cytometry [4,[27][28][29][30][31]. We also found that flow cytometry yielded significantly lower amounts of BMPC compared with smear morphology, which further confirms that it is the least reliable method to discriminate between plasma cell myeloma and MGUS.…”

Morphologic and cytogenetic variables affect the flow cytometric recovery of plasma cell myeloma cells in bone marrow aspirates

“…Recently, Manasanch et al . documented roughly a 50% morphologic decrease in second‐pull compared with first‐pull aspirates. These authors also documented that EDTA anticoagulation was associated with decreased viability in first‐pull aspirates compared with heparin, suggesting that first‐pull, heparin‐anticoagulated aspirates are the bone marrow specimen of choice for the flow cytometric evaluation of myeloma.…”

Disease detection methodologies in relapsed B‐cell acute lymphoblastic leukemia: Opportunities for improvement

“…Notably, almost 1/3 of the FC results were reported to have significant hemodilution that can impact the accuracy of MRD detection. 23 The majority of discrepancies were noted between BM biopsy and FC reports. Importantly, 14/49 discrepant cases identified to be in a com- can vary dramatically between modalities tested.…”

“…Our results demonstrate that disease detection discordance in the relapsed/refractory setting occurs more frequently than has been previously reported and was seen in approximately 15% of BM cases evaluated and approximately one‐third of all patients evaluated. Notably, almost 1/3 of the FC results were reported to have significant hemodilution that can impact the accuracy of MRD detection . The majority of discrepancies were noted between BM biopsy and FC reports.…”