Acute rheumatic fever
ARF occurs within 10 days to six weeks after an episode of gas pharyngitis, although the causative infection may be subclinical. It occurs as a nonsuppurative complication of gas pharyngitis in susceptible hosts. While the underlying mechanisms of arf not well understood, the key event is inappropriate activation of the immune system, leading to autoimmune attack.
Invading pathogens trigger innate immune responses, leading to inflammation. During the inflammatory responses, immune cells are attracted to the site of infection and are exposed to antigenic compounds. Antigenic compoundsin gas infection include the M-protein, hyaluronic acid coat and exotoxins.