Inflammation in cystic fibrosis--when and why? Friend or foe?

Pulmonary infection and an excessive neutrophil-driven inflammatory response are responsible for most of the morbidity and mortality associated with cystic fibrosis. Although inflammation is first and foremost a protective response to injury or infection it has the potential to cause considerable harm when it is excessive. Whereas most published reports emphasize the damaging effects of the chronic inflammatory response in cystic fibrosis, the beneficial effects are more difficult to quantify. Low levels of inflammation may assist in clearing infection, particularly early in the disease process, and surges of acute inflammation may be beneficial during exacerbations. Anti-inflammatory therapies are used to modify the inflammatory response but there is clearly a need to preserve the protective aspects of the inflammatory response because host defense and a fine balance exist between benefit and harm. The underlying processes involved in the inflammatory response are reviewed along with current and future anti-inflammatory therapies.