Granulomatosis with polyangiitis (GPA) is a rare type of blood vessel inflammation (called vasculitis) that most often affects the sinuses, lungs and kidneys. GPA is a potentially serious disease that can reduce blood supply to vital organs and, if left untreated, can lead to kidney failure and lung complications.

It is a rare disease


GPA affects an estimated three out of every 100,000 people.


It affects men and women equally. It can occur at any age, but occurs most often between the ages of 40 and 65.

What are GPA and MPA?

Granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA)  are two types of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs).

Vasculitis means the inflammation of blood vessels, it is not a single disease, but an umbrella term referring to many disorders that are characterized by inflammation of the blood vessels, which can restrict blood flow and damage vital organs and tissues.


AAV is a form of vasculitis that affects the small blood vessels in your body and causes inflammation in the small blood vessels.This inflammation may cause the layers of the blood vessel wall to thicken, which narrows the blood vessel and reduces the amount of blood that can flow through it. This reduction in blood flow can cause serious problems and even damage the body's organs.

In general, AAV affects the sinuses, kidneys, lungs, and skin, but the ways the diseases show themselves vary.

GPA and MPA can worsen rapidly, therefore early diagnosis and treatment are essential to prevent organ damage.

What causes GPA and MPA?

The cause of GPA and MPA is not yet fully understood. They are both autoimmune disorders, in which your body’s immune system, its defense against infection, attacks healthy tissues.

• Antibodies are found in the blood and are produced by the immune system. Their job is to fight germs and other outside invaders. 

• In GPA and MPA, a harmful type of antibody known as an autoantibody (an antibody attacking healthy tissues) is produced. 

• The autoantibody often involved in GPA and MPA is known as ANCA. ANCAs act against the body’s own healthy tissues and cells. They cause inflammation that targets and attacks the blood vessel walls in different organs in the body. 



  1. American College of Rheumatology:
  2. Calabrese LH, Molloy ES, Duna Gf. Antineutrophil cytoplasmic antibody-associated vasculitis. In Kelley’s Textbook of Rheumatology, 2009; Edited by GS Firestein, RC Budd, SE Gabriel, et al. Philadelphia, PA: Saunders/Elsevier.
  3. Pagnoux C. Updates in ANCA-associated vasculitis. Eur J Rheumatol 2016; 3:122-133.

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