3/16/2018 8:44:00 AM Rare autoimmune disease attacks blood vessels
DEAR DOCTOR: My brother died from Wegener's disease at age 62. Could you please tell me more about this disease -- what causes it and what can be done? Could there be a connection to the fact that our father died of rheumatoid arthritis at age 64?
DEAR READER: I'm sorry to hear about the loss of your brother -- and understand your desire to learn more about this rare disease. For starters, Wegener's is named after Friedrich Wegener, the German pathologist who defined it. In recent years, Wegener's has been called granulomatosis with polyangiitis (GPA), which more accurately describes the disease. Granulomatosis refers to masses of scar tissue, and polyangiitis refers to inflammation of blood vessels.
An autoimmune condition that affects one to two per 100,000 people per year, GPA is usually linked to an abnormal protein called ANCA, for antineutrophil cytoplasmic antibody. ANCA attacks two types of white blood cells, monocytes and -- more important -- neutrophils.
Neutrophils normally help fight infections by ingesting and killing bacteria. They also help in the inflammatory response to injury. ANCA, however, causes the neutrophils to inflame normal tissue. It also causes them to release chemicals normally reserved for killing bacteria, causing even greater destruction to normal tissue. This dual assault affects the smaller blood vessels of the body, especially in the respiratory system and in the kidneys; symptoms can progress either slowly (over several months) or rapidly (over a matter of days).
The hallmark of the disease is vascular inflammation of the organs, most notably the lungs, affecting their air spaces and leading to scar tissue that forms nodules within them. In a severe form of GPA, the small blood vessels leak blood into the air spaces, causing a sudden drop in a person's oxygen level. This is turn leads to a coughing-up of blood and the failure of the respiratory system.
In most cases -- 90 percent -- GPA also affects the sinuses, nose, ears, mouth or throat. These symptoms can appear similar to those caused by common nasal congestion, sinusitis or a runny nose. But as the disease progresses, it can cause ulcers in the nose and mouth, hearing loss and the destruction of nose cartilage, resulting in nasal deformities.
The kidneys don't escape attack either. Because blood is filtered by the small vessels of the kidneys, inflammation of these blood vessels compromises the kidneys' filtering mechanism. Early damage can be diagnosed through tests that detect protein in the urine, but ultimately about 80 percent of people with GPA will develop severe kidney problems within two years of diagnosis -- and many will have kidney failure.
GPA can also damage the eyes, the skin and the nervous system.
Because the disease is, in effect, an autoimmune attack, treatment focuses on suppressing the immune system with steroids and other drugs. Although these drugs have side effects, they're effective in controlling the disease. Once remission occurs, patients can switch to milder immune-suppressing drugs. Note that the disease can reoccur, however, sometimes induced by infection.
Why the disease develops is unknown. It's possible that an infection may lead to the formation of ANCA, causing GPA; genetic factors may play a role as well. In fact, one study found similar genetic changes in GPA and rheumatoid arthritis, so your father's history of rheumatoid arthritis may be a factor. As you can see, however, more research is needed. You're not alone in wanting answers.
(Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.)
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