Revisiting the role of interleukin-8 in chronic lymphocytic leukemia

Sci Rep. 2017 Nov 16;7(1):15714. doi: 10.1038/s41598-017-15953-x.

Abstract

The proliferation and survival of malignant B cells in chronic lymphocytic leukemia (CLL) depend on signals from the microenvironment in lymphoid tissues. Among a plethora of soluble factors, IL-8 has been considered one of the most relevant to support CLL B cell progression in an autocrine fashion, even though the expression of IL-8 receptors, CXCR1 and CXCR2, on leukemic B cells has not been reported. Here we show that circulating CLL B cells neither express CXCR1 or CXCR2 nor they respond to exogenous IL-8 when cultured in vitro alone or in the presence of monocytes/nurse-like cells. By intracellular staining and ELISA we show that highly purified CLL B cells do not produce IL-8 spontaneously or upon activation through the B cell receptor. By contrast, we found that a minor proportion (<0.5%) of contaminating monocytes in enriched suspensions of leukemic cells might be the actual source of IL-8 due to their strong capacity to release this cytokine. Altogether our results indicate that CLL B cells are not able to secrete or respond to IL-8 and highlight the importance of methodological details in in vitro experiments.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Apoptosis
  • Cell Line, Tumor
  • Cell Survival
  • Female
  • Humans
  • Interleukin-8 / metabolism*
  • Leukemia, Lymphocytic, Chronic, B-Cell / metabolism*
  • Leukemia, Lymphocytic, Chronic, B-Cell / pathology
  • Male
  • Middle Aged
  • Monocytes / metabolism
  • Receptors, Interleukin-8 / metabolism

Substances

  • CXCL8 protein, human
  • Interleukin-8
  • Receptors, Interleukin-8