Background: Myelodysplastic Syndromes (MDS) are a group of clonal hematopoietic stem cell disorders with significant heterogeneity in their clinical presentation and the prognosis of the patients. Several attempts have been made to incorporate flow cytometry (FC) findings into the diagnostic and/or prognostic criteria of dysplasia, but bone marrow (BM) aspirate morphology evaluation remains the gold-standard for diagnosis. The purpose of this study was to provide a diagnostic tool for MDS that relies on BM immunophenotyping and objectifies the interpretation of FC analysis and to validate its capacity to discriminate MDS from other causes of cytopenias.
Methods: To that purpose, a mathematical formula was developed which incorporates granulocytic maturation markers and the percentage of selected myeloid populations and translates them into a single parameter that quantifies the maturation and differentiation defects of BM granulocytes, named Dysmyelopoiesis Index (DMI). Bone marrow samples from 84 MDS patients and 47 non-MDS cytopenic patients were analyzed with FC and DMI was calculated for every patient.
Results: DMI detected clonal dysplasia with 84.5% sensitivity and 93.6% specificity, identified as MDS 77.2% of low grade patients and revealed multilineage dysplasia for a number of RA and RARS cases. It discriminated prognostic subgroups of MDS patients (P< .005) and negatively correlated with IPSS (r= - .472, P= .000), WPSS (r= - .481, P= .000) and IPSS-R (r= -.395, P= .000).
Conclusions: DMI represents an accurate quantification of dysmyelopoiesis and an effective stand-alone diagnostic test for MDS, facilitating FC analysis and daily clinical practice.