Myeloid and monocytic dyspoiesis as determined by flow cytometric scoring in myelodysplastic syndrome correlates with the IPSS and with outcome after hematopoietic stem cell transplantation.

Marrow cells of myeloid lineage from 115 patients with myelodysplastic syndrome (MDS) were characterized by multidimensional flow cytometry and compared with findings in 104 patients with various disorders and 25 healthy donors. Based on phenotypic and scatter characteristics, a flow cytometric scoring system (FCSS) was developed that allowed for a simple numerical display of results. The flow cytometric scores were categorized as normal/mild (0-1), moderate (2-3), or severe (> or = 4). Most flow cytometric abnormalities were significantly (P <.05) more frequent in patients with MDS than in the control cohort. Flow cytometric scores in MDS patients were then retrospectively compared with marrow blast counts assessed by morphology, cytogenetics, hematologic parameters, and International Prognostic Scoring System (IPSS) risk categorization. The flow cytometric scores correlated inversely with leukocyte and absolute neutrophil counts (P <.01) and correlated directly with IPSS scores (P <.01) and with IPSS cytogenetic risk categories (P <.01). In 111 MDS patients who underwent allogeneic hematopoietic stem cell transplantation, flow scores correlated with posttransplantation outcome. The probabilities of posttransplantation relapse were 3%, 15%, and 33% for patients with mild, moderate, and severe FCSS scores, respectively (P <.01), and overall survival was 74%, 40%, and 36%, respectively, for the 3 groups (P <.01). In multivariate analyses, there was a significant contribution of the flow score independent of the IPSS in predicting survival and relapse (P <.01, P =.02, and P =.03, respectively). These data suggest that FCSS is useful in assessing marrows for diagnosis of MDS and in determining the prognostic outcome in patients with this disorder.