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Sjögren’s Syndrome
Sjögren’s syndrome is a disorder of the immune system, where glands
that normally produce tears, saliva and sweat are attacked and
destroyed by immune cells. This results in abnormally dry eyes, mouth
and/or other mucous membranes, such as the intestines, lungs or
vagina.
Sjögren’s syndrome may occur by itself, known as Primary Sjögren’s
syndrome, or together with other autoimmune diseases, such as Systemic
Lupus Erythematosus (also known as lupus or SLE) and rheumatoid
arthritis. This is known as Secondary Sjögren’s syndrome. The cause of
Sjögren’s syndrome is still a bit of a mystery, though there appears to
be a genetic influence, as it tends to occur in families where there
are other autoimmune diseases.
Although there is no cure for Sjögren’s syndrome, proper treatment
should provide comfort and relief of symptoms.
The average time from onset of symptoms to diagnosis of Sjögren’s syndrome is six years.
Sjögren’s syndrome is caused by a problem of the immune system. The
immune system normally protects the body against foreign matter, like
bacteria and viruses. However, in autoimmune diseases, for reasons
which are not fully understood, the immune cells attack the body’s own
cells and tissues. In Sjögren’s syndrome, immune cells infiltrate and
destroy the mucus-producing glands of the body. It is thought that
several factors, including viral infections, hormones, genetics and
stress, trigger autoimmune diseases.
The symptoms of Sjögren’s syndrome vary greatly between individuals.
They include a dryness of the moist areas of the body, like the mouth,
eyes, ears, nose and vagina. Fatigue and depression, plus painful
joints, are also associated with the disease.
As there is currently no cure for Sjögren’s syndrome, treatment is
aimed at symptomatic relief. A variety of artificial tear preparations
can be used to treat dry eyes. There are some oral lubricants for
treating symptoms of a dry mouth, but none are entirely satisfactory.
Chewing sugarless gum is helpful for some people. Good dental hygiene
and frequent visits to the dentist are essential. Moisturisers can help
people with dry skin and lubricating creams may be helpful with dryness
of the vagina. Oral medications, including non-steroidal
anti-inflammatory drugs, may be used to treat swollen and painful
joints.
Recently, Garvan researchers identified sub-forms of Sjögren’s
syndrome that are triggered by mechanisms that to date have been
thought to have little to do with this disease. Sjögren’s syndrome is
believed to be caused by improper regulation of two immune cell types,
T and B cells, which comprise the ‘adaptive’ half of the immune system
that responds specifically to antigens (foreign substances). Indeed, in
many patients this is the case.
Garvan’s scientists have shown that many patients suffering from
Sjögren’s syndrome have high levels of something called B
cell-activating factor (BAFF) in their blood serum, as well as locally
in their glands. BAFF plays a critical role in B cell survival and
immune responses. We have now demonstrated that high levels of BAFF
enable B cells to progress the disease without the help of T cells,
which was previously thought to be essential for the development of
Sjögren’s syndrome. This is an important breakthrough that will allow
Garvan scientists to develop a new generation of therapeutic agents for
Sjögren’s syndrome that specifically target auto-reactive B cells.
Patients who have this form of the disease will then be able to trial
more tailored and effective treatments.
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