NOX2-dependent immunosuppression in chronic myelomonocytic leukemia
Johan Aurelius1,2, Alexander Hallner2, Olle Werlenius1,2
1Department of Hematology, Sahlgrenska University Hospital, Gothenburg, Sweden.
Journal of Leukocyte Biology
|March 16, 2017
Summary
Chronic myelomonocytic leukemia (CMML) cells evade immune attack by releasing reactive oxygen species (ROS). This immunosuppressive mechanism causes lymphocyte death, offering a potential therapeutic target for CMML treatment.
Area of Science:
- Hematology
- Immunology
- Oncology
Background:
- Chronic myelomonocytic leukemia (CMML) is a rare blood cancer with limited treatment options.
- The role of immune cells, like natural killer (NK) cells, in CMML pathogenesis is not well understood.
Purpose of the Study:
- To investigate the mechanisms by which CMML cells evade immune surveillance.
- To explore the role of reactive oxygen species (ROS) in CMML immune evasion.
Main Methods:
- Primary human CMML cells were analyzed for NADPH oxidase-2 (NOX2) expression and ROS production.
- Coculture experiments were performed with CMML cells and various immune cells (NK cells, CD8+ T cells).
- The impact of ROS inhibitors and scavengers on immune cell survival and function was assessed.
Main Results:
- CMML cells express NOX2 and release immunosuppressive ROS, inducing PARP-1-dependent death in NK and T cells.
- Inhibiting ROS production or scavenging extracellular ROS protected lymphocytes from CMML-induced death and enhanced NK cell activity.
- Increased immature CD34+ cell counts in CMML patients correlated with reduced NK cell-activating receptor expression.
Conclusions:
- CMML cells utilize extracellular ROS as a mechanism to suppress anti-leukemic immune responses.
- Targeting ROS production or scavenging represents a potential therapeutic strategy for CMML.
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