C-ANCA stands for "Cytoplasmic Antineutrophil Cytoplasmic Antibodies." It is a type of autoantibody that can be found in the blood of individuals with certain autoimmune diseases, particularly those associated with a group of conditions known as ANCA-associated vasculitis (AAV). ANCA-associated vasculitis is a group of rare autoimmune disorders that cause inflammation of blood vessels (vasculitis). These conditions can affect various organs in the body, including the kidneys, lungs, skin, and other tissues.