Circulating endothelial cells in patients with chronic lymphocytic leukemia.

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Circulating endothelial cells in patients with chronic lymphocytic leukemia.

S Go, Dean A Jobe, Krista E Asp, M Callister, A

Mathiason, Lori A Meyer, Wayne A Bottner, Craig E Cole, P Farnen, and

Kathleen A Frisby

Ann Hematol, January 12, 2008; .

Center for Cancer and Blood Disorders, Gundersen Lutheran Health System, 1900

South Avenue, Mail Stop: EB2-001, 54601, La Crosse, Wisconsin, USA,

rsgo@....

Angiogenesis is increased in B-cell chronic lymphocytic leukemia (B-CLL). We

wanted to quantify and characterize the circulating endothelial cells (CECs) in

patients with B-CLL and correlate with plasma angiogenesis-related factors.

Using a four-color flow cytometry, we prospectively analyzed the CEC in the

whole blood of 20 healthy controls and 20 patients with B-CLL. We quantified

(CD45-/CD31+/CD146+) and characterized the CECs according to whether they were

apoptotic (annexin stain) or activated (CD106+). We also measured plasma levels

of vascular endothelial growth factor (VEGF), fibroblast growth factor-2

(FGF-2), and thrombospondin-1 (TSP-1). Most patients (90%) had Rai stages 0-2 at

the time of diagnosis. As a group, B-CLL patients had higher number of CECs

(median of 26.5 cells/ml) compared (P = 0.04) to healthy controls (18.5

cells/ml). However, only four (20%) patients had elevated CEC counts, defined as

>/=2 SD of the control mean (>/=53 cells/ml). The proportions of apoptotic (P =

0.83) and activated (P = 0.12) CECs were similar in both groups. B-CLL patients

had higher FGF-2 (P < 0.001), lower TSP-1 (P = 0.004), and similar VEGF (P =

0.27) plasma levels. The number of CECs was not associated with Rai stage,

absolute lymphocyte count, or levels of angiogenesis-related factors. CECs are

increased in only a small fraction of B-CLL patients in our cohort with low

rates of apoptosis and activation. While no correlation was found between CECs

and clinical features, more studies in a larger patient sample size and advanced

disease are necessary.

PMID: 18193423