Cancer, Age and Immunity

Aging and the effects of immune system impairment on cancer

(RxWiki News) Immuno-therapy refers to any attempt to change the regulation of the immune system, usually by coaching the immune system of patients to attack cancer cells.

Researchers recently found that previous beliefs about immunotherapy not being effective when used in the elderly aren't quite true.

The less toxic side effects of immunotherapy are generally preferred to more traditional cancer treatments like chemotherapy and radiation treatment.

Yet previous research concluded that the immune systems of the elderly are less likely to respond to immunotherapy due to age-related decline in immune function, and testing supported this.

"Ask your oncologist about immunotherapy."

Researchers from the University of Texas Health Science Center were working on a new cancer drug trial in mice when they found out that the issue was more complicated than previously believed. The immune system of older mice worked differently, involving another cell that side-stepped the cancer drug.

Modifying the immunotherapy by adding another drug gave even better results than expected.

Mice are preferred for testing involving the immune system because their immunity is nearly identical to humans.

The drug worked in mice both young and old, but but the cancer continued to progress in old mice. Researchers found that an additional type of immune cell was present that is absent in younger mice, a myeloid-derived suppressor cell which prevents the treatment from working.

Adding a secondary drug to target the myeloid-derived suppressor cells made all the difference, and the response was even better once another additional immunotheray drug was added to the therapy to counteract the myeloid derived suppressor cells.

"We've shown that immunotherapy for cancer not only works in aged mice, but actually can work better in aged hosts than in young counterparts by capitalizing on the immune changes that happen with age," said Tyler Curiel, MD, the study author.

In the study design, researchers analyzed immunotherapy with Ontak (denileukin diftitox) in treating melanoma and colon cancer tumors placed in mice. While the drug combinations used to treat each cancer in older mice were not identical, by modifying the treatment to account for the difference in immune function caused by age, effective results were achieved.

Researchers announced plans to begin a clinical studies in humans to verify their findings.

The paper was published on April 15 in the journal Cancer Research.

This study was funded in part by the Voelcker Foundation and the Holly Beach Public Library Association. No other financial disclosures were made.

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Review Date: 
April 20, 2012