Researchers at the University of Pennsylvania and international collaborators have shown that innate immune training, also known as trained immunity (TRIM), leads to aggravated bone loss in experimental models of periodontitis and inflammatory arthritis. “Although TRIM can have beneficial effects—protecting against infections and cancer—the memory of a previous infection may also contribute to inflammatory diseases and the comorbidity between inflammatory bone loss disorders,” says George Hajishengallis of Penn Dental Medicine.