Cancer cells that reduce MHC class I—a common way to evade CD8+ “killer” T cells—may become more vulnerable to destruction by CD4+ “helper” T cells through ferroptosis, according to research led by Baylor College of Medicine and collaborators at the University of Michigan and published in Nature Immunology.
Researchers led by Dr. Pavan Reddy, director of the Dan L Duncan Comprehensive Cancer Center at Baylor College of Medicine, reported that when tumor cells downregulate MHC class I, they can become more susceptible to elimination by CD4+ T cells. Using functional studies in mouse models and analyses of human samples, the team found that reduced MHC class I expression on target cells was associated with CD4+ T cell-triggered ferroptosis, an iron-dependent form of oxidative cell death. The study also extended the observations beyond cancer, reporting similar effects in experimental models of graft-versus-host disease, a potentially severe complication after bone marrow transplantation. To assess clinical relevance, the researchers analyzed transcriptomic and clinical datasets from patients treated with immune checkpoint inhibitors for solid tumors and reported correlations between the newly described immune mechanism and patient outcomes.
