A buildup of dysfunctional “zombie” immune cells may be a major driver of aging and fatty liver disease. Removing them in mice reversed liver damage—even without changing an unhealthy diet. Credit: Shutterstock UCLA scientists have uncovered a harmful group of immune cells that quietly builds up in aging tissues and in the livers of people with fatty liver disease. When these cells were removed in mice, inflammation dropped sharply and liver damage was reversed, even though the animals