Chimeric Antigen Receptor T-cell (CAR-T) therapy has revolutionised cancer treatment, especially for aggressive and previously untreatable cancers. This cutting-edge immunotherapy involves collecting a patient’s T cells, genetically modifying them to recognize and attack cancer cells more effectively, and then reintroducing them into the bloodstream.
While the results in fighting cancer have been promising-with many patients achieving long-term remission-scientists are now uncovering a concerning side effect: mild cognitive impairments, commonly described as 'brain fog.'
New study reveals link between CAR-T therapy and brain fog
A team of researchers from Stanford University, led by Professor Michelle Monje, has discovered that CAR-T therapy may lead to symptoms such as forgetfulness, difficulty concentrating, and slower thinking. These cognitive changes can occur even when the treatment is used against cancers that are completely outside the brain.
Their findings, published in the journal Cell, show that this mental fogginess isn’t just an offshoot of other treatments like chemotherapy. Instead, it stems from a shared biological mechanism that also underlies cognitive issues seen in patients recovering from chemotherapy and viral infections like influenza and COVID-19.
Further research
To investigate further, the research team conducted experiments on mice that had cancers in various parts of the body-including the brain, skin, blood, and bones. They assessed the mice’s cognitive abilities both before and after CAR-T treatment using memory-based tasks, such as exploring new objects and solving simple mazes according to IANS
Interestingly, most mice exhibited signs of cognitive decline regardless of where their cancer originated. Only those with bone cancers that triggered minimal immune responses did not develop noticeable impairments
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The Brain's Role
The culprit behind this cognitive side effect appears to be inflammation within the brain. The study pointed to microglia specialised immune cells in the brain-as key players. When activated, these cells can inadvertently disrupt normal brain function, leading to symptoms associated with brain fog.
The immune response generated by the engineered T cells seems to overstimulate the microglia, which then impacts cognitive performance. This happens even if the CAR-T cells are not directly targeting brain tissue.
Hope for recovery
Despite the concerns, the researchers are optimistic. The study also identified potential medications that could help mitigate these cognitive symptoms. By targeting the inflammatory processes or supporting healthy brain cell activity, scientists believe it’s possible to reverse or reduce the impact of immunotherapy-related brain fog.
