Anti-proteinase 3 (PR3) antibody

Anti-proteinase 3 (PR3) antibody is a type of autoantibody, meaning it mistakenly targets the body's own cells—in this case, a protein called proteinase 3 found in certain immune cells. These antibodies are often associated with a condition called granulomatosis with polyangiitis (GPA), a rare disorder that causes inflammation and damage to blood vessels, especially in the respiratory tract and kidneys. The presence of anti-PR3 antibodies helps doctors diagnose this disease and understand its activity, guiding treatment to reduce inflammation and prevent organ damage.