For many years Sjögren's syndrome has been an elusive diagnosis and an even more elusive disease once diagnosed. That is changing.
Sjögren's syndrome has been defined a number of different ways since first described in 1892 as parotid and lacrimal gland enlargement. Now Sjögren’s syndrome is considered a disorder of all the moisture-producing glands, such as the tear glands (lacrimal glands) and the salivary glands. These glands become infiltrated with white blood cells (lymphocytes) that are part of our immune system. This causes the glands to produce less moisture, leading to dryness of the eyes and mouth. In some cases, lymphocytes also infiltrate internal organs such as the lungs, the kidneys, the nervous system, the liver, and the intestines. Because these infiltrates can affect multiple organs, they can cause a wide variety of symptoms.
In the last few years, scientists' views of Sjögren’s syndrome has changed dramatically. It is now known that Sjögren's syndrome is associated with increased levels in cerebrospinal fluid (CSF) of IL-1RA, an interleukin 1 antagonist. This suggests that the disease begins with increased activity in the interleukin 1 system, followed by an auto-regulatory up-regulation of IL-1RA to reduce the successful binding of interleukin 1 to its receptors. Interleukin 1 is the likely marker for fatigue, but increased IL-1RA is observed in the CSF and is associated with increased fatigue through cytokine-induced sickness behavior . At the same time, there are decreased levels of IL-1ra in the saliva.
One of the bigger changes is that the diagnostic criteria for Sjögren's syndrome have changed. Until 2012 the American-European Consensus Group (AECG) criteria were used. Diagnosis of primary Sjögren’s syndrome required at least four of the criteria listed below. In addition, either criterion number 5 or criterion number 6 had to be included. Sjögren’s syndrome could be diagnosed in patients who had no sicca symptoms if three of the four objective criteria were fulfilled. The criteria are:
- Ocular symptoms: Dry eyes for more than 3 months, foreign-body sensation, use of tear substitutes more than 3 times daily
- Oral symptoms: Feeling of dry mouth, recurrently swollen salivary glands, frequent use of liquids to aid swallowing
- Ocular signs: Schirmer test performed without anesthesia (< 5 mm in 5 min), positive vital dye staining results
- Oral signs: Abnormal salivary scintigraphy findings, abnormal parotid sialography findings, abnormal sialometry findings (unstimulated salivary flow < 1.5 mL in 15 min)
- Positive minor salivary gland biopsy findings
- Positive anti–SSA or anti–SSB antibody results
Secondary Sjögren’s was diagnosed when, in the presence of a connective tissue disease, symptoms of oral or ocular dryness exist in addition to criterion 3, 4, or 5 above.
The main difficulty was that Primary and Secondary Disease were considered different. Because fewer criteria were applied to secondary disease, it was considered “less serious.” Anyone with secondary Sjögren’s knows that just isn't true.
By 2012 the definitions of Primary and Secondary were changed. Primary was when the only disease present was Sjögren’s (or most of the symptoms) Secondary Sjögren’s was when other auto-immune disease is present. Consequently, diagnostic criteria changed. Once the clear autoimmune connection was identified, new criteria were identified, as it was necessary to improve criteria used for entry into clinical trials, especially in light of the emergence of biologic agents as potential treatments for Sjögren’s syndrome and their associated co-morbidities.
This high specificity makes the ACR criteria more suitable for application in situations where misclassification may present a health risk. They were accepted by the ACR as a provisional criteria set in 2012.
According to the ACR criteria, the diagnosis of Sjögren’s syndrome requires at least two of the following three findings:
- Positive serum anti-SSA and/or anti-SSB antibodies or positive rheumatoid factor and antinuclear antibody titer of at least 1:320
- Ocular staining score of at least 3
- Presence of focal lymphocytic sialadenitis with a focus score of at least 1 focus/4mm2 in labial salivary gland biopsy samples
The ACR criteria are based entirely on a combination of objective tests that assess the three main components of Sjögren’s syndrome (serologic, ocular, and salivary) and do not include criteria based on subjective symptoms of ocular and oral dryness.
Application of these criteria has yielded a sensitivity of 93% and a specificity of 95% for the diagnosis of Sjögren’s syndrome, meaning there is a very good probability of obtaining an accurate diagnoses using these criteria. These criteria do not distinguish between primary and secondary forms of Sjögren’s syndrome. Not all doctors are applying the new criteria, but the number doing so is increasing dramatically.
There is currently a blood test marketed by IMMCO called the SJO but has more to do with ocular dryness and is pretty much exclusivley used by ophthalmologists and sadly naturopaths to sell their wares. Its an ANA test, and doesn't prove anything.