Clapper, Patti, Schweizer and Mason

A recent report published in Cancer Immunology, August 2010, from scientists at Hokkaido University in Japan shows support of using CD8+ T cells as a form of immunotherapy and positive prognostic factor for mesothelioma.  The results of their study indicate that the stimulation of CD8+ tumor infiltrating lymphocytes lead to a more favorable prognosis for patients diagnosed with malignant pleural mesothelioma (MPM.)

Mesothelioma is a rare malignancy that can develop in the pleura (lining of the lungs), peritonea (lining of the abdomen), or pericardia (lining of the heart.)  Exposure to asbestos causes mesothelioma, although symptoms do not appear until 20-50 years after time of exposure.  Although the use of asbestos is highly regulated and reduced in developed countries, due to the long latency period, the incidence of mesothelioma is expected to continue to rise in the near future.  To date, there is no cure or sign of optimal treatment, and prognosis remains poor.  Because of this, research continues to search for more effective treatments.

One line of research is immunotherapy.  Research over the years have led to the definitive conclusion that tumors are immunogenic, meaning that there is a high feasibility that stimulating an immune response could be therapeutically effective in preventing and treating solid tumors.

Immunotherapy for mesothelioma stimulates the immune system by use of a variety of reagents, one of which is the infusion of T cells, also known as cytokines.  This infusion is known to stimulate an antitumor response and suppress further progression of cancer cells. 

MPM has shown response and regression with the administration of immune-modulators, especially with interleukin 2 (IL-2).  Recent studies have shown that IL-2 creates a heightened number of CD8+  lymphocytes and enhances they lymphocyte activity and improves the overall survival rate of MPM patients.

The study from Japan further supports findings that a higher density of tumor infiltrating lymphocytes (TILs), particularly CD8+ along with helper CD4+ cells, indicated better prognosis in patients diagnosed with mesothelioma, and therefore that further research into the stimulation of CD8+ as a component of combined treatment is recommended.