Researchers in Western Australia are investigating new ways of bolstering the immune system in an effort to fight cancers like mesothelioma.
Like most types of cancer, malignant mesothelioma occurs primarily in people over 65. That is also the time in life when the immune system typically weakens. Researchers from Curtin University and the University of Western Australia say it is no coincidence that people become more susceptible to mesothelioma as their immunity wanes. In addition to age-related immune dysfunction, mesothelioma patients experience a further decline in immunity caused by the growing tumor itself.
To better understand the connection between declining immunity and the onset of mesothelioma, the researchers are focusing on a particular type of immune system cell called a macrophage. Macrophages are white blood cells that help to remove debris and pathogens from the body while stimulating an immunity response in other immune system cells.
“Macrophages make up to 50 percent of the mesothelioma and lung cancer tumor burden,” observed Curtin University’s Dr. Connie Jackaman in a recent online article at Science Network. Jackaman says this could make macrophages “a viable therapeutic target if we can understand how they function with age and tumor suppression.”
When the research teams exposed both young and old mice to fluid produced by mesothelioma and lung cancer tumors, the old mice showed a “more immunosuppressive tumor microenvironment.” When older mice were treated with a type of immunotherapy (IL-2 anti-CD40 antibody), macrophages in the old mice were reactivated, restoring the production of tumor-fighting T-cells. This result suggests that, if macrophages could be appropriately activated in human mesothelioma patients, it could theoretically “rescue both age-related and tumor-induced immune dysfunction.”
The researchers say their next step will be to see if they can cause tumors such as mesothelioma to shrink in live patients by targeting their macrophages.
Mesothelioma is a rare but highly aggressive cancer of the membranes around internal organs. It is directly related to asbestos exposure. Australia has one of the highest per capita rates of mesothelioma in the world.
“Targeting macrophages rescues immune dysfunction in the elderly”, May 28, 2013, Science Network, Western Australia.