Diet and gut microbes drive fragile T cells behind immunotherapy side

Researchers at the University of Pittsburgh report a mechanism that may help explain why many patients struggle with immunotherapy’s immune-related adverse events. In a study in Cell, the team found that a population of unstable immune cells, pushed into a fragile state by diet and gut bacteria, drives the inflammatory damage behind these toxicities. Results came from a new mouse model and were supported with patient samples. The work focuses on immune checkpoint inhibitors, which improve outcomes by releasing brakes on T cells, but can also trigger inflammation in healthy tissues. Depending on the drug, 20% to 40% of patients experience immune-related adverse events, and up to 25% develop severe episodes that stop treatment and lead to hospitalization.