Some patients being treated with immune checkpoint inhibitors, a type of cancer immunotherapy , develop a dangerous form of heart inflammation called myocarditis. Researchers led by physicians and scientists at the Broad Institute of MIT and Harvard and Massachusetts General Hospital (MGH), a founding member of the Mass General Brigham healthcare system, have now uncovered the immune basis of this inflammation. The team identified changes in specific types of immune and stromal cells in the heart that underlie myocarditis and pinpointed factors in the blood that may indicate whether a patient's myocarditis is likely to lead to death.

Appearing in Nature , the results are among the earliest translational findings to come from the Severe Immunotherapy Complications (SIC) Service and Clinical-Translational Research Effort, which is based at Mass General Cancer Center and includes Broad researchers. Launched in 2017, this is a first-of-its-kind program in North America focused on improving the diagnosis , treatment, and understanding of serious immunotherapy complications, which can affect nearly every organ system. The team focused on myocarditis as one of their first research projects because despite being one of the rarer complications from immune checkpoint inhibitors (ICIs), it is the most deadly.

Importantly, these findings provide the first evidence for an immune reaction in the heart that is distinct from the immune response at the tumor, suggesting that targeted treatmen.