Diagnostic application of flow cytometry in myelodysplastic syndromes

Background: The diagnosis of myelodysplastic syndrome (MDS) is based on a combination of clinical history,morphological assessment, genetic studies and the exclusion of other diseases. Diagnosing MDS in uncertainmorphology, especially in patients with normal karyotype or low myeloblast count remains a challenging issue.Objective: The primary objective was to evaluate the sensitivity and specificity of an in-house 12-parameter flowcytometry scoring method for diagnosing MDS. Materials and Methods: We collected 48 patients with cytopenia ofunknown cause. The diagnosis of MDS was made using the WHO 2016 criteria. Flow cytometry criteria using12 parameters included the following markers: %CD34, CD7/CD13 expression in progenitor cells, side scatter(SSC) of granulocyte/lymphocyte ratio, CD13CD16, CD16CD11b, CD13CD11b, CD15CD10 expression in maturingneutrophils, CD36CD14, %CD56 in monocyte, %CD34+CD10+ B-cells, CD71CD235a and CD36/CD235a in erythroidcells. The sensitivity and specificity of flow cytometry score for diagnosing MDS were analyzed. To validatethe scoring method, we applied the panel to another set of cytopenic patients (n = 45) and evaluated its performance.Result: Of the 48 patients, 36 were diagnosed with MDS, while 12 did not meet the diagnostic criteria.A multiparameter flow cytometry score ≥ 3 showed 77.7% sensitivity, 100% specificity, 100% positive predictivevalue and 60% negative predictive value for MDS diagnosis. The parameters %CD34, SSC of granulocyte/lymphocyte ratio, CD13CD16, CD11bCD13, CD11bCD16 and CD71CD235a were strong indicators for MDS diagnosis.When applied to the validation set (n = 45), the results were comparable to those of the training set. Conclusion:Multiparameter flow cytometry is helpful in diagnosing MDS with inconclusive morphology. A score ≥ 3 appearsto be an appropriate cut-off value for diagnosis.