Cytokine-driven loss of plasmacytoid dendritic cell function in chronic lymphocytic leukemia

Damien Saulep, Fabien Vincent, Melanie Le Page, Andrew Wei, Stephen Bek Ngie Ting, Carlo M Croce, Constantine Tam, Fabienne Mackay-Fisson

Research output: Contribution to journalArticleResearchpeer-review

25 Citations (Scopus)

Abstract

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of CD5(+)CD19(+) B cells in the peripheral blood, and in primary and secondary lymphoid organs. A major complication associated with CLL is severe recurrent infections, which are often fatal. Vulnerability to infection is due to a wide variety of immunological defects, yet the initiating events of immunodeficiency in CLL are unclear. Using CLL patient samples and a mouse model of CLL, we have discovered that plasmacytoid dendritic cells (pDCs), which underpin the activity of effector immune cells critical for anti-viral immunity and anti-tumor responses, are reduced in number and functionally impaired in progressive CLL. As a result, the levels of interferon alpha (IFNa) production, a cytokine critical for immunity, are markedly reduced. Lower pDC numbers with impaired IFNa production was due to the decreased expression of FMS-like tyrosine kinase 3 receptor (Flt3) and Toll-like receptor 9 (TLR9), respectively. Reduced Flt3 expression was reversed using inhibitors of TGF-? and TNF, an effect correlating with a reduction in tumor load. Defects in pDC numbers and function offer new insight into mechanisms underpinning the profound immunodeficiency affecting CLL patients and provide a potentially novel avenue for restoring immunocompetency in CLL.
Original languageEnglish
Pages (from-to)2005 - 2015
Number of pages11
JournalLeukemia
Volume28
Issue number10
DOIs
Publication statusPublished - 2014

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