What are GPA and MPA?

Granulomatosis with Polyangiitis (GPA) (formerly known as Wegener's Granulomatosis) and Microscopic Polyangiitis (MPA) are two types of ANCA-associated vasculitis, or AAV. AAV is a form of vasculitis that primarily affects the small blood vessels in your body. In general, AAV affects the sinuses, kidneys, lungs, and skin, but the ways the diseases show themselves vary.

About ANCA-Associated Vasculitis (AAV)

AAV 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.

ANCAs play a role in GPA and MPA

Antibodies are found in the blood and are produced by the immune system. Their job is to fight germs and other outside invaders. But in GPA and MPA, a harmful type of antibody known as an autoantibody (pronounced aw-toh-AN-ti-bod-ee) 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.

ANCAs are usually present in GPA and MPA, but there are times when this is not the case. Your doctor will perform a blood test to look for ANCAs.

Marked by periods of flares and remission

In GPA and MPA, there are periods of flares and periods of remission. Flares occur when your symptoms worsen or new symptoms appear. Remission, on the other hand, is a long or short period of time after a flare when symptoms are controlled or go away.

Since GPA and MPA are chronic diseases, they never completely go away. So even when you are in remission, your doctor may prescribe other therapies to control your disease. Keep in mind that everyone's experience is different, so it's hard to predict when a flare may occur.