Rheumatic fever after group A streptococcal infections involves autoimmune attack on which cardiac structures?

• A. Endocardium and heart valves
• B. Myocardium
• C. Cardiac muscle
• D. Pericardium

Answer: (A)

Rheumatic fever is an autoimmune reaction that follows infection with Group A Streptococcus, driven by antibodies that cross-react with heart tissue due to molecular mimicry. The heart can be affected in all layers (pancarditis), but the autoimmune injury most characteristic of this process targets the endocardium and the heart valves. Inflammation of the valve endocardium (valvulitis) leads to damage that can scar and deform the valves, causing stenosis or regurgitation over time. While myocarditis and pericarditis can occur as part of the broader inflammatory response, the structures most specifically attacked in this autoimmune process are the endocardium and the heart valves.