For some cancer patients, the effects of immunotherapy can linger in an unexpected place: their joints. Painful arthritis may return repeatedly, sometimes becoming more severe with each episode. Now, scientists have uncovered a possible explanation involving the immune system's ability to remember previous attacks.

Researchers at The University of Texas MD Anderson Cancer Center have found evidence that arthritis triggered by certain cancer immunotherapies behaves like a disease driven by immune memory. Rather than launching an entirely new inflammatory response during each flare, the immune system appears to reactivate cells involved in earlier episodes.

The discovery could eventually help doctors identify patients at risk of recurring arthritis and develop treatments that control joint inflammation without interfering with the immune system's ability to fight cancer.

The study, published in Cancer Immunology Research , was led by scientists at UT MD Anderson and Yale University.…