Integration of automated morphological features resolves a distinct group of atypical chronic lymphocytic leukemias with chromosomal aberrations

Automated morphological assessment of peripheral blood slides has become an important modality facilitating characterization and quantification of cells in a uniform, fast and robust manner. In this study, we evaluated the morphological diversity in peripheral blood films of 94 chronic lymphocytic leukemia (CLL) patients using the DM1200 CellaVision automated microscopy system. Aberrant lymphocytes and smudge cells were enumerated and correlated with CLL immunophenotype, chromosomal aberrations and prognostic parameters. Herein, we show that the percentages of aberrant and smudge cells was highly variable between patients and did not correlate with each other. Increased aberrant lymphocytes and fewer smudge cells were associated with an atypical immunophenotype including low expression of CD23, higher levels of FMC7 and bright surface levels of CD20. High fraction of aberrant lymphocytes also was associated with trisomy 12. These cells were predominantly of small/medium size, sometimes with cleft nuclei. No correlation was noted between aberrant or smudge cells and clinical stage, CD38, ZA70 or time to first treatment. Taken together, automated morphological analysis of peripheral blood leukocytes emerged as a powerful and robust tool for the quantitative morphological stratification of CLL. Integration of the automated morphological features discriminates between different CLL phenotypes and distinct chromosomal aberrations.