Pathophysiology of rheumatic heart disease
After your child has the GAS infection of the pharynx, his (her) body releases neutrophils and macrophages to phagocyte the organism. The body recognizes the antigen of GAS and presents it to T cells. B and T cells release antibodies (IgM and IgG) against these antigens.
This immune reaction may trigger an autoimmune response against the body tissues. The antibodies bind to the antigen of body tissues, which leads to inflammation of the heart, brain, joint, and subcutaneous tissue. The antibody may bind to basal ganglia, causing chorea. Also, it binds to keratin (of the skin), causing subcutaneous nodules.
The antibodies bind to the heart tissue, causing inflammation of the myocardium and permanent injury of heart valves. The T cells infiltrate the valves, which damages the endothelium and causes remodeling of the valvular structure. Destruction of the valves causes collagen release and deposition, which accelerates their injury.
