In Search of a Clonal Assay for Myeloid Neoplasia by Flow Cytometry

Objectives: To determine whether the fraction of CD177+ neutrophils might be altered in clonal myeloid disorders, similar to the skewed k/l ratio for B-cell lymphomas, and could be used to identify myeloid neoplasms. Methods: Blood and bone marrow samples were evaluated for the fraction of CD177+ neutrophils by flow cytometry. Results: Skewed high neutrophil CD177(%) was not associated with neoplasia, but skewed low neutrophil CD177(%) was highly correlated with clonal myeloid disorders at values less than 40%. Specificity of low neutrophil CD177(%) for clonal myeloid disorders was 87% with a 40% cutoff and 95% with a 30% cutoff. Findings were most pronounced for myelodysplasia, with 52% (11/21) containing fewer than 40% CD177+ neutrophils. Specificity was also suggested by normalization of neutrophil CD177(%) in four patients who reached morphologic remission after therapy for myelodysplasia or acute leukemia. Conclusions: Skewed low neutrophil CD177(%) is highly associated with clonal myeloid disorders, particularly myelodysplasia, and may be useful for detecting clonal