Expression of CD163 and HLA-DR molecules on the monocytes in chronic lymphocytic leukemia patients.

Introduction: Human peripheral blood monocytes are the part of the leukemia microenvironment. We examined three monocyte subgroups: classical (CD14++CD16-), intermediate (CD14++CD16+) and non-classical (CD14+CD16++) monocytes. As these subpopulations can be also characterized by different levels of HLA-DR and CD163, we evaluated their expression on monocyte subpopulations of patients with chronic lymphocytic leukemia (CLL) and healthy individuals. Material and

Methods: The monocyte subsets in peripheral blood of CLL patients (n = 40) and healthy controls (n = 10) were evaluated by flow cytometry. The monoclonal antibodies: anti-CD14 FITC, anti-CD16 PE-Cy5, anti-CD163 PE, anti-HLA-DR PE were used.

Results: The percentage of CD16-positive monocytes was significantly higher in CLL patients than in healthy donors. The highest percentage of CD163+ monocytes is in the 'classical' (CD14++CD16-) population. In turn, the non-classical monocytes constituted the majority of cells lacking HLA-DR expression. In CLL patients, there was no statistically significant relationship between the percentage of each monocyte subpopulation and the stage according to Rai Staging of CLL.

Conclusions: The presence of CD163 on classical monocytes suggests that these cells have anti-inflammatory properties. Besides, the low expression of HLA-DR on non-classical monocytes may result in impaired ability to stimulate the immune system.