Principles of inflammation for the pediatrician.

The immune system consists of 2 branches: innate and adaptive. The former represents the first line of host defense during infection and plays a key role in the early recognition and protection against invading pathogens. The latter orchestrates elimination of pathogens in the late phase of infection and leads to the generation of immunologic memory. Innate and adaptive immunity should not be considered separate compartments. Innate and adaptive immune responses represent an integrated system of host defense. The authors review the mechanisms driving the induction and perpetuation of the inflammatory responses observed during pathogen-associated, autoimmune, and autoinflammatory diseases.