Absolute Monocyte Count Trichotomizes Chronic Lymphocytic Leukemia Into High Risk Patients With Immune Dysregulation, Disease Progression and Poor Survival

Peripheral blood absolute monocyte count (AMC) has been reported to correlate with clinical outcome in different types of cancers. This association may relate to alteration in circulating monocytic subpopulations and tumor infiltrating macrophages. In this study we evaluated the clinical significance of peripheral blood AMC in 80 treatment naive patients with CLL. The measurement of AMC was based on morphological enumeration using an automated microscope (CellaVision DM1200), due to our findings that automated complete blood count data may yield incorrect monocytes enumeration values in CLL. The median AMC in patients with CLL was not different from normal controls, however the AMC range exceeded the values of healthy individuals (median of 458/µL with a of range 0-4868/µL in CLL vs. median of 310/µL with a range of 105-1154 in healthy controls). The AMC divided the patients into 3 distinct sub-groups with different characteristics and outcomes. Patients with high AMC (>750/µL) were younger and also had higher absolute lymphocytes counts, while patients with low AMC (<250/µL) had prominent immune dysregulation (lower serum IgA levels, susceptibility to infections and a tendency for positive direct anti-globulin test). The low and high AMC patients had a shorter time to treatment compared to the intermediates AMC subgroup (250-750/µL), whereas low AMC was associated with increased mortality caused by infectious complications. In conclusion, AMC quantification during the disease course classifies CLL patients into subgroups with unique clinical features and outcomes.