High CXCR3 on Leukemic Cells Distinguishes IgHV^mut from IgHV^unmut in Chronic Lymphocytic Leukemia: Evidence from CD5^high and CD5^low Clones

Abstract

Despite the shared pattern of surface antigens, neoplastic cells in chronic lymphocytic leukemia (CLL) are highly heterogeneous in CD5 expression, a marker linked to a proliferative pool of neoplastic cells. To further characterize CD5high and CD5low neoplastic cells, we assessed the chemokine receptors (CCR5, CCR7, CCR10, CXCR3, CXCR4, CXCR5) and adhesion molecules (CD54, CD62L, CD49d) on the CD5high and CD5low subpopulations, defined by CD5/CD19 coexpression, in peripheral blood of CLL patients (n=60) subgrouped according to the IgHV mutational status (IgHVmut, n=24; IgHVunmut, n=36). CD5high subpopulation showed a high percentage of CXCR3 (P<0.001), CCR10 (P=0.001), and CD62L (P=0.031) and high levels of CXCR5 (P=0.005), CCR7 (P=0.013) compared to CD5low cells expressing high CXCR4 (P<0.001). Comparing IgHVmut and IgHVunmut patients, high levels of CXCR3 on CD5high and CD5low subpopulations were detected in the IgHVmut patients, with better discrimination in CD5low subpopulation. Levels of CXCR3 on CD5low subpopulation were associated with time to the next treatment, thus further confirming its prognostic value. Taken together, our analysis revealed higher CXCR3 expression on both CD5high and CD5low neoplastic cells in IgHVmut with a better prognosis compared to IgHVunmut patients. Contribution of CXCR3 to CLL pathophysiology and its suitability for prognostication and therapeutic exploitation deserves future investigations.

Towards a Better Characterisation of Leukemic Cells in Chronic Lymphocytic Leukaemia: Cell-Size Heterogeneity Reflects Their Activation Status and Migratory Abilities

“…Correlation analyses revealed a significant positive association of CD5 high and CD5 low cells with the percentages of CXCR3-positive cells, as indicated in our previous study [ 5 ]; this was also visualised by immunofluorescent staining ( Figure 3 C). The percentage of CLL cells in the patients’ blood negatively correlated with the percentage of s-CLL and l-CLL cells that tested positive for HLA-DR (r = −0.59, p < 0.01 and r = −0.48, p < 0.05, respectively) and CD20 MFI (r = −0.55, p < 0.01 and r = −0.56, p < 0.01 respectively).…”

“…The CLL cells from all the blood samples were stained with optimal concentrations of antibody combinations and directed against the following surface antigens: CD183(CXCR3)-FITC, CD20-PE, CD5-PerCP-Cy5.5, CD38-Pe-Cy7, CD49d-APC, CD19-APC-Cy7, CD184 (CXCR4)-BV421 and HLA-DR-BV510 (all procured from BioLegend), as previously reported [ 5 , 15 ]. Isotype-matched antibodies (BioLegend) were used as negative controls.…”

“…Chronic lymphocytic leukaemia (CLL) is characterised by the clonal expansion of mature CD19 + CD23 + CD5 + B-cells in the blood, bone marrow and lymphoid tissue [ 1 ]. CLL cells are characterised by their phenotypic, clonal and functional heterogeneity and contain a pool of resting and proliferating CLL subpopulation cells [ 2 , 3 , 4 , 5 , 6 ]. The inverted expression of CD5 and CXCR4 has been indicated as useful for identifying enriched fractions among recently born/divided and elderly/quiescent CLL cells [ 2 , 3 , 7 ].…”