Quantitative Flow Cytometry Immunophenotypic Data in Myelodysplastic Syndromes (MDS)

Abstract

Background: Recent studies using qualitative analysis of flow cytometry data have demonstrated various im- munophenotypic abnormalities associated with myelodysplastic syndromes (MDS). However, there are limited reports as- sessing the ability of quantitative immunophenotypic analysis to discriminate MDS from other cytopenic conditions. Design: Using flow cytometry, we studied 37 bone marrow specimens from 23 patients with MDS and 14 cytopenic pa- tients with non-clonal hematologic disorders. Samples were analyzed quantitatively for percentages of T-cells, B-cells, NK cells, granulocytes, monocytes, blasts, erythroid precursors, and plasma cells; CD4:CD8 ratio; % granulocyte subsets; % CD56+ monocytes; and % erythroid precursor subsets. Results: Quantitative analysis of immunophenotypic data in MDS patients compared to controls showed decreases in total granulocytes (p=0.037) and more mature subsets of CD11b + CD16 bright granulocytes (p=0.0046) and CD10 + granulocytes (p=0.022). MDS patients also showed a trending increase in subset percentage of CD56+monocytes (p=0.056). Using re- ceiver operating characteristic (ROC) analysis, cut-off values for these parameters favoring a diagnosis of MDS were identified as follows: total granulocytes 10%. Subsequently, a scoring system was proposed whereby a score of one was assigned for the presence of each quantitative abnormality. Using this system on the original study population, the pres- ence of at least two abnormalities (score 2) revealed optimal sensitivity (69.6%) and specificity (71.4%) for a diagnosis of MDS. Conclusion: These findings suggest that quantitative analysis of immunophenotypic data can be complementary to quali- tative interpretation. These data may be useful for distinguishing MDS from non-clonal cytopenic disorders and warrant prospective study in additional MDS patients.