Multiparameter flow cytometry reveals myelodysplasia‐related aberrant antigen expression in myelodysplastic/myeloproliferative neoplasms

Background: Within the myelodysplastic/myeloproliferative neoplasm (MDS/MPN) category of the WHO (2008), only chronic myelomonocytic leukemia was so far evaluated by multiparameter flow cytometry (MFC). Methods: To investigate the potential of MFC for MDS/MPNs, unclassifiable (MDS/MPNu), and refractory anemia associated with ring sideroblasts and marked thrombocytosis (RARS‐T), we studied 91 patients with these entities (60 males/31 females; 35.3–87.4 years) for MDS‐related aberrant immunophenotypes (≥2 different cell lineages with ≥3 aberrantly expressed antigens). Data were correlated with cytomorphology and cytogenetics. Results: MFC identified MDS‐related immunophenotypes in 54/91 (59.3%) of patients. Patients with or without MDS‐related immunophenotype did not differ significantly by demographic characteristics, blood values, or median overall survival. MDS‐related immunophenotype cases showed a higher number of aberrantly expressed antigens (mean ± SD, 4.9 ± 2.4 vs. 2.0 ± 1.4; P < 0.001). Aberrant karyotypes showed a similar frequency in patients with and without MDS‐related immunophenotype (11/54; 20.4% vs. 7/37; 18.9%; P = n.s.). Conclusions: MDS‐related immunophenotype are present in more than half of patients with MDS/MPNu and RARS‐T. MFC therefore may be helpful to separate cases into more “MDS‐like” or “MPN‐like” subgroups. © 2012 International Clinical Cytometry Society