What is an autoimmune disease?
The human body seems to be under almost constant attack from the outside world, whether it is from harsh climate, from the sun's ultraviolet rays, or the bacteria and viruses that surround us. So, it seems especially unfair when the body attacks itself to cause illness. This is precisely what occurs in a group of illnesses referred to as autoimmune diseases. Autoimmune diseases can affect almost anyone. Imagine what happens when lymphocytes, a type of white blood cell, decide that organs in the body are alien and don't belong. They mount an attack and invade and infiltrate that organ, causing it to fail. That is autoimmune disease in a nutshell.
What is Sjögren's syndrome?
In Sjögren's syndrome, the lymphocytes attack glands whose secretions pass through a duct directly to the outside of the body. The most common complaints are dry eyes and dry mouth, since the glands that make tears and saliva are affected. (It's important to remember that most people with dry eyes and dry mouth have it because of other, non-serious causes.) Sjögren's syndrome would less serous if those were the only issues, but the syndrome can also involve the lungs, kidney, liver, and skin. Moreover, it can rarely be associated with a form of cancer of the lymph glands called lymphoma.
What causes Sjögren's syndrome?
There are plenty of theories as to what causes the autoimmune attack to start, and there may be an association with rheumatoid arthritis, systemic lupus erythematosus, and scleroderma. The diagnosis of Sjögren's syndrome is often challenging because patients often (in addition to the classic dry eyes and dry mouth) complain of nonspecific symptoms such as:
How is Sjögren's syndrome diagnosed?
It's also a tough diagnosis because there isn't total agreement as to criteria for the diagnosis. There can be abnormal blood tests, including autoantibodies (rheumatoid factor or RF, and antinuclear antibody or ANA), and tests looking for inflammation such as erythrocyte sedimentation rate or ESR. There are antibodies in the blood that can be found in many, but not all patients with the Sjögren's syndrome. These antibodies are referred to as Sjögren's syndrome antibodies A and B (also known as SSA or Ro antibody and SSB or La antibody). Biopsies of salivary glands can be done to help confirm that lymphocytes have invaded the gland. There are consensus guidelines for making the diagnosis, but mostly it comes down to the doctor having a high index of suspicion and pursuing it.
If only the eyes and mouth are involved, treatment is aimed to control symptoms, but aggressive medications may be needed if major organs like the lung, liver, and kidney are involved. Again, another concern is that patients can (though uncommonly) develop non-Hodgkin's lymphoma cancer. Most patients, however, do well and their prognosis is based on whether other autoimmune diseases like lupus and rheumatoid arthritis are also involved.
Medically reviewed by Kirkwood Johnston, MD; American Board of Internal Medicine with subspecialty in Rheumatology
"Diagnosis and classification of Sjögren's syndrome"