Serum interleukin-6, cardiovascular disease, and mortality in chronic lymphocytic leukemia.

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BlankSerum interleukin-6, cardiovascular disease, and mortality in chronic

lymphocytic leukemia.

Sub-category: Leukemia

Category: Leukemia, Myelodysplasia, and Transplantation

Meeting: 2010 ASCO Annual Meeting

Citation: J Clin Oncol 28:7s, 2010 (suppl; abstr 6581)

Abstract No: 6581

Author(s): D. E. Dawe, J. Yoon, S. Gibson, J. B. ston; Department of

Internal Medicine, University of Manitoba, Winnipeg, MB, Canada; Manitoba

Institute of Cell Biology, Winnipeg, MB, Canada; CancerCare Manitoba, Manitoba

Institute of Cell Biology, Winnipeg, MB, Canada; CancerCare Manitoba, Manitoba

Institute of Cell Biology, Department of Internal Medicine, University of

Manitoba, Winnipeg, MB, Canada

Abstract:

Background: Interleukin-6 (IL-6) plays an integral role in the process of aging

and autoimmunity and contributes to the increased incidence of cardiovascular

disease. IL-6 levels may be elevated in chronic lymphocytic leukemia (CLL) but

whether these patients also have an increased incidence of cardiovascular

disease leading to mortality is unknown. Methods: 193 patients (107 males, 86

females; ages, 37-92 yr (median, 67.6 yr) with CLL attending CancerCare Manitoba

between 1/1/04 and 30/12/08 were evaluated. There were an equal number of

patients aged < 65 yrs and = 65 yrs. Serum IL-6 levels were determined by an

ELISA assay. Cardiovascular disease was defined as any symptom referable to the

cardiac, neurovascular or peripheral vascular system and/or vascular procedures.

Results: Plasma IL-6 levels ranged from < 0.01 to 93.1 pg/mL (median, 1.43

pg/mL). The median plasma IL-6 level in 37 age- and sex-matched controls was

0.83 pg/mL (range, 0.06-8.11 pg/mL). Using a cut-off of 3 pg/mL to define an

elevated IL-6 level, high IL-6 levels occurred in 23% of patients and levels

correlated with Rai stage, ß2-microglobulin and age. The median number of

traditional cardiac risk factors did not differ between patients with high and

low IL-6 (1.66 ± 1.1 vs. 1.52 ± 1.1, respectively). Patients with cardiovascular

disease had increased IL-6 (p < 0.05) and there was a trend to a higher

incidence of cardiovascular disease in patients with high IL-6 (36.4% vs. 22.8%,

p = 0.07). In addition, patients with high IL-6 had considerably increased

mortality as 31.8% of patients with high IL-6 died versus 12.8% for patients

with low IL-6 (p = 0.003). This mortality difference was amplified in those = 65

years old (42.8% vs. 10.4%, p = 0.0003). The major causes of death were

progressive CLL, second malignancies, and infections. Conclusions: Thus, high

levels of IL-6 in CLL are associated with a significantly increased risk of

mortality and this is most evident in those =65 years old. Although

cardiovascular disease is not the primary cause of death, it is associated with

high levels of IL-6 and may contribute to progression of CLL.