So what is Sjogren's, really?
Updated: Nov 14
Sjogren’s is called an autoimmune rheumatic disease (AIRD).
This is a useful label because Sjogren’s is closely related to other AIRDs such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and systemic sclerosis (SSc). These four diseases have overlapping features, comorbidities, and autoantibodies. While a large majority of patients with RA, SLE, and SSc have autoantibodies, occasionally they do not. On the other hand, about 30-40% of Sjogren’s patients do not test positive for SS-A, the autoantibody that is used to support a Sjogren’s diagnosis (6).
Does this mean Sjogren’s is always autoimmune?
You may be surprised to find out that there is no clear answer to this. “Autoimmune” actually means something more specific than the “the body attacking itself”. Autoimmune diseases are associated with autoantibodies. Calling Sjogren’s an “autoimmune disease” is oversimplified, but works well in most circumstances. Most clinicians and many rheumatologists use the term "autoimmune disease" to refer to any disease where the body's own immune system attacks normal tissues.
The “autoimmune” label can become a problem if your rheumatologist won’t diagnose you or treat you for Sjogren’s because your “blood tests don’t show it”. They may say that autoantibodies, especially SSA, must be present to have the disease. However, SSA negative (seronegative) Sjogren’s is quite common. Other autoantibodies may also be seen in Sjogren's, although these are not yet routinely used for diagnosis. More research is needed to understand the pathways that lead to Sjogren's disease, and how they may differ in different groups of patients.
SSA is not specific to Sjogren’s. It is often present alongside other rheumatic diseases such as SLE and SSc (166). SSA is sometimes found in people with infections such as hepatitis C and COVID-19. Some healthy people carry SSA and never develop Sjogren’s (14). Clearly, we need better tests! Sjogren’s is a complex disease. What drives the immune system to mistakenly attack the body is still not completely understood. Autoantibodies serve as helpful biomarkers (indicators) for diagnosis when patients have them. In Sjogren’s, the role of autoantibodies in the disease process remains unclear (166).
The “autoimmune” label may get in the way of Sjogren’s care if:
Your rheumatologist won’t diagnose you with Sjogren’s because you don’t have autoantibodies, especially SSA. Myth buster: Many people (30% or more) with Sjogren’s don’t have SSA or other typical autoantibodies such as SSB, ANA, or RF that are typically associated with Sjogren’s. Other autoantibodies may support a Sjogren's diagnosis and help guide treatment, including anti-centromere antibody (ACA). More autoantibodies are being studied to better understand their role in Sjogren's disease. See MYTHS ABOUT DIAGNOSIS for more self-advocacy tools.
Your SSA was positive but turns negative on a follow-up test. As a result, your rheumatologist tells you that you no longer have Sjogren’s. Myth buster: Sjogren’s does not go away. If you have clinical features of Sjogren's, once you test positive for SSA, it is not recommended to repeat the test because this changes may be misinterpreted. SSA titers do not go up and down with disease activity. Sometimes SSA disappears. This does not mean Sjogren's is better or no longer present.
Your rheumatologist does not monitor or treat you for Sjogren’s because you don’t have autoantibodies such as SSA. Some clinicians incorrectly believe that Sjogren’s patients without SSA don’t develop serious systemic features. Myth buster: While SSA is a risk factor for certain complications and comorbidities, patients without SSA may also develop serious systemic disease. Some serious outcomes are more common in SSA positive patients, while others are more common in SSA negative patients. Every Sjogren’s patient deserves the full range of monitoring and treatment, regardless of SSA status (139).
See this blog post to learn more about "seropositive" vs "seronegative" Sjogren's.
Sjogren’s may be both autoimmune and autoinflammatory.
It is clear that Sjogren’s is a chronic systemic inflammatory disease. It is never just a sicca disease, although sicca is serious and present in most people with Sjogren's.
Sjogren’s is a complex immune-mediated disease. Subtypes of Sjogren’s may involve different immune system pathways that lead to the same disease (168). The causes of Sjogren's, like other immune mediated diseases, are not fully understood.
From the Spondylitis Association website
Simple Definitions These definitions are simplified, and may change as we learn more about the complex immune system pathways that lead to immune-mediated diseases.
Immune-mediated disease - a disease that is caused when a malfunctioning immune system attacks the body. Autoimmune and autoinflammatory diseases are types of immune-mediated diseases. Many immune-mediated diseases, including Sjogren’s, are rheumatologic. Others, such as multiple sclerosis, are not rheumatologic.
Autoimmune disease - an immune-mediated disease thought to be driven by the "adaptive immune system", usually associated with autoantibodies. Unlike people with rheumatoid arthritis or systemic lupus erythematosus, people with Sjogren's are more likely to test negative for typical autoantibodies. However, many other autoantibodies have been found by researchers (153). Their role in Sjogren's diagnosis has not been determined. At this time, autoantibody testing is usually limited to SSA, SSB, ANA and RF.
Autoinflammatory disease - an immune-mediated disease thought to be driven by the innate immune system. There are no associated autoantibodies.
For an introduction to the immune system, check out these beautiful and brief IMMUNE SYSTEM VIDEOS.
Many of the medical terms on this page have been added to the Glossary. The link to the Glossary is located in the footer (the bottom) of every page.
