Translating the MDS flow cytometric score into clinical practice

Abstract

Myelodysplastic syndromes (MDS) are classified by the WHO as myeloid neoplasms, and are characterized by cytopenia and dysplasia in one or more myeloid cell lines. Recently, a flow cytometric score (FCM-score) was published capable of discriminating low-grade MDS from non-clonal cytopenias (Della Porta et al., 2012). We tested the applicability of the FCM-score in a patient population from a large peripheral teaching hospital in The Netherlands.The evaluation of the proposed FCM score in low-grade MDS showed a high sensitivity and specificity, and clinically significant positive and negative likelihood ratios. The use of CD10 and CD19 positivity to identify progenitor B-cell blasts provided a specific and precize method to separate progenitor B-cell blasts from myeloid blasts within the CD341/low CD451 population and may be more convenient compared to the published method using low SSC and CD45 expression. This study confirms the value of utilizing the FCM-score in our patient population. Myelodysplastic syndromes (MDS) are classified by the WHO as myeloid neoplasms, and are characterized by cytopenia and dysplasia in one or more myeloid cell lines (1). They are the result of ineffective hematopoiesis that leads to an increased risk of developing acute myeloid leukemia. When patients lack specific diagnostic markers, such as clonal cytogenetic abnormalities and/or ringsideroblasts, the diagnosis MDS is not always straightforward. Recently, a flow cytometric score (FCM-score) was published capable of discriminating low-grade MDS from nonclonal cytopenias (2). We tested the applicability of the FCM-score in a patient population from a large peripheral teaching hospital in The Netherlands.The FCM algorithm as proposed by Della Porte et al. (2) measures four cardinal parameters (cutoff): CD341 myeloid blast cells (2%) and CD341 B-progenitorrelated cluster size (5%), lymphocyte/myeloid blast cell CD45 mean fluorescence intensity (MFI) ratio (4 or 7.5) and granulocyte/lymphocyte side scatter peak channel ratio (<7). Patients scored 1 point for each fulfilled criteria. An FCM-score of 2 or more was considered suggestive for the diagnosis of MDS.Separating B-progenitor blasts from myeloid blasts by sidescatter characteristics and CD45 expression, as proposed by this algorithm, can be difficult and may "pollute" the B-progenitor related cluster with myeloid blasts or vice versa. To improve the separation of B-

Comparison of flow cytometry with other modalities in the diagnosis of myelodysplastic syndrome

“…The Ogata Score performed with reasonable sensitivity and high specificity, as has been reported by others. 11,[13][14][15] The specificity of the flow cytometry score was similar to that of aspirate morphology and trephine morphology, and the sensitivity of flow cytometry was comparable to trephine morphology.…”

Screening bone marrow samples for abnormal lymphoid populations and myelodysplasia‐related features with one 10‐color 14‐antibody screening tube

“…The MDS score, which we applied based on analysis of the screening tube, has been developed by Ogata et al. It has been subsequently validated in a multinational study and in a routine diagnostic practice . Recently, a prognostic significance of this score has also been reported .…”

“…This score has been validated in an international study and has been reported to be of prognostic significance in MDS patients . It has been recommended to be used for screening purposes by the International/European Leukemia Net Working Group for Flow Cytometry in MDS and confirmed as useful in clinical practice .…”

Usability of femoral head bone marrow to verify reference ranges for the assessment of myelodysplasia by flow cytometry

“…In this study, we applied the FCS, a cumulative score of 4 IPSs to our sample population, initially reported by Della Porta et al, and subsequently validated in a single center study . Aalbers et al evaluated the FCS score in children with dysplasia.…”

“…In this study, we applied the FCS, a cumulative score of 4 IPSs to our sample population, initially reported by Della Porta et al, and subsequently validated in a single center study. 9,10 Aalbers et al 11 evaluated the FCS score in children with dysplasia. The four IPS and cutoff levels comprise of: (a) CD34 + myeloblast-related cluster size (≥2%), (b) B-cell progenitor-related cluster size (≤5%), (c) granulocyte to lymphocyte SSC ratio (≤6), and (d) lymphocytes to myeloblasts CD45 ratio (≤4 or ≥7.5).…”