Antineutrophil Cytoplasmic Antibodies (ANCA)

Antineutrophil Cytoplasmic Antibodies (ANCA) are special proteins produced by the immune system that mistakenly target the body's own neutrophils, a type of white blood cell involved in fighting infections. This misdirected attack can cause inflammation of blood vessels, a condition called vasculitis, which may affect organs like the kidneys, lungs, or skin. Testing for ANCA helps doctors diagnose certain autoimmune diseases, such as granulomatosis with polyangiitis (GPA) and microscopic polyangiitis, guiding appropriate treatment to reduce inflammation and prevent organ damage.