The mechanism of the development of Acute Rheumatic Fever is which of the following? (AIPG 2012)
|A||Cross reactivity with exogenous antigen|
|B||Innocent bystander effect|
|C||Due to toxin secretion by streptococci|
|D||Release of pyrogenic cytokines|
Acute rheumatic fever results from immune response to group A streptococci (Strep. pyogenes) which cross-reacts within host tissues. The antibodies directed against the M proteins of streptococci cross reacts with the self antigens in the heart. In addition, CD4+ T cells specific for streptococcal peptides also react with self proteins in the heart and produce macrophage activating cytokines. So, the damage to the heart tissue is a combination of antibody and T-cell mediated reactions.