Diagnostic utility of flow cytometry in low-grade myelodysplastic syndromes: a prospective validation study

Abstract

The online version of this article contains a supplementary appendix. BackgroundThe diagnosis of myelodysplastic syndromes is not always straightforward when patients lack specific diagnostic markers, such as blast excess, karyotype abnormality, and ringed sideroblasts. Design and MethodsWe designed a flow cytometry protocol applicable in many laboratories and verified its diagnostic utility in patients without those diagnostic markers. The cardinal parameters, analyzable from one cell aliquot, were myeloblasts (%), B-cell progenitors (%), myeloblast CD45 expression, and channel number of side scatter where the maximum number of granulocytes occurs. The adjunctive parameters were CD11b, CD15, and CD56 expression (%) on myeloblasts. Marrow samples from 106 control patients with cytopenia and 134 low-grade myelodysplastic syndromes patients, including 81 lacking both ringed sideroblasts and cytogenetic aberrations, were prospectively analyzed in Japan and Italy. ResultsData outside the predetermined reference range in 2 or more parameters (multiple abnormalities) were common in myelodysplastic syndromes patients. In those lacking ringed sideroblasts and cytogenetic aberrations, multiple abnormalities were observed in 8/26 Japanese (30.8%) and 37/55 Italians (67.3%) when the cardinal parameters alone were considered, and in 17/26 Japanese (65.4%) and 42/47 Italians (89.4%) when all parameters were taken into account. Multiple abnormalities were rare in controls. When data from all parameters were used, the diagnostic sensitivities were 65% and 89%, specificities were 98% and 90%, and likelihood ratios were 28.1 and 8.5 for the Japanese and Italian cohorts, respectively. ConclusionsThis protocol can be used in the diagnostic work-up of low-grade myelodysplastic syndromes patients who lack specific diagnostic markers, although further improvement in diagnostic power is desirable.Key words: myelodysplastic syndromes, flow cytometry, diagnosis.Citation: Ogata K, Della Porta MG, Malcovati L, Picone C, Yokose N, Matsuda A, Yamashita T, Tamura H, Tsukada J, and Dan K. Diagnostic utility of flow cytometry in low-grade myelodysplastic syndromes: a prospective validation study. Haematologica 2009;94:1066-1074. doi:10.3324/haematol.2009 This is an open-access paper. Diagnostic utility of flow cytometry in low-grade myelodysplastic syndromes: a prospective validation study

Standardization of flow cytometry in myelodysplastic syndromes: a report from an international consortium and the European LeukemiaNet Working Group

“…13,22 The SSC of maturing neutrophils is recommended to be expressed as a ratio relative to that obtained for lymphocytes as an internal reference. The peak channel value for determination of the SSC ratio was reported to have less inter-operator variability, 33 although this parameter is not available in all analysis software.…”

“…To avoid a pitfall in such cases, SSC evaluation of specific maturation-associated compartments, such as CD10-negative (immature) neutrophils, might be helpful. 33 Of note, mature neutrophils in MDS can aberrantly lack CD10. 22,35,36 Moreover, differences in SSC may be observed for different sample preparation procedures (i.e., distinct lysing solutions and fixatives).…”

“…To circumvent problems regarding hemodilution in the enumeration of progenitor B cells, it is recommended to express these cells as fraction of all CD34 þ blast cells. 33,54 The relevance of a decreased percentage of B-cell progenitors is not yet known, as it is also seen in the elderly population without MDS. Interestingly, a decreased relative amount of progenitor B cells (o5% of CD34 þ cells) was recently introduced as one of the cardinal parameters in a model to distinguish low-risk MDS from non-clonal cytopenias.…”

“…Interestingly, a decreased relative amount of progenitor B cells (o5% of CD34 þ cells) was recently introduced as one of the cardinal parameters in a model to distinguish low-risk MDS from non-clonal cytopenias. 33 It should be noted that a relative decrease in B-cell progenitors can result from an increase in myeloid progenitor cells, especially in high-risk MDS.…”

“…To illustrate this, multicenter validation (on behalf of the ELN) recently confirmed the ability to distinguish low-risk MDS without other specific markers (i.e., cytogenetics or ring sideroblasts) from non-clonal cytopenias by application of only four parameters. 33 These parameters are an increased percentage of CD34 þ progenitor cells in a bone marrow sample, a decreased number of progenitor B cells within the CD34 þ compartment, a decreased or increased CD45 expression on myeloid progenitor cells and a decreased SSC of neutrophils. In this study, additional useful markers were CD10, CD15, CD11b and CD56.…”