Blocking a protein that stimulates the production of white blood cells could prevent the destructive inflammation of COPD, a study with mice shows.

Chronic inflammation slowly eats away at the lung tissue of people with emphysema or COPD, and the major culprits are specialized white blood cells called neutrophils and macrophages. While adept at fighting lung infections, the cells can also attack the lungs’ elastic fibers, leaving people struggling for breath and prone to chest infections.

There is no cure, and while abnormally high levels of white blood cells have long been associated with emphysema, scientists haven’t been sure about an underlying cause that drugs could effectively target.