Most people with scleroderma have autoantibodies. Several scleroderma-specific antibodies have been identified. These can help with diagnosis and give insight into the type of disease you may experience.
Scleroderma is an autoimmune disease that affects connective tissue. The National Scleroderma Foundation estimates that around 300,000 people in the United States are living with scleroderma.
In scleroderma, increases in inflammation lead to the thickening in the skin and sometimes in internal organs. Experts refer to this thickening as fibrosis.
Scleroderma is associated with the presence of specific autoantibodies. These are proteins that can attack healthy tissues in your body.
Here, we cover more about the role of antibodies in scleroderma. We’ll also discuss how testing for antibodies is used in the diagnosis of scleroderma, what happens if an antibody test is positive, and more.
Antibodies are proteins made by your immune system that bind to specific substances called antigens. Typically, antigens are foreign substances like bacteria or viruses.
In some autoimmune diseases, antibodies are specific for an antigen found in healthy tissue. These are called autoantibodies. Binding of autoantibodies to their antigens can cause an immune response, leading to inflammation and tissue damage.
Autoantibodies are very prevalent in scleroderma and there are several different types that may be present. Experts have estimated that
Which autoantibodies are positive in scleroderma?
A variety of different autoantibodies can be present in people with scleroderma. These are collectively referred to as anti-nuclear antibodies (ANAs).
ANAs are autoantibodies that bind to antigens found in the nucleus of the cell. They may bind to many
An estimated
- anti-centromere (ACA)
- anti-topoisomerase I (ATA), also called the anti-SCL-70
- anti-RNA polymerase III (RNA Poly III)
There are also a few more scleroderma-related ANAs, although these are less common. According to the National Scleroderma Foundation, these are:
- anti-fibrillarin (U3RNP)
- anti-PM-Scl
- anti-Ku
- anti-Th/To
- anti-U11/U12 RNP
- anti-U1 RNP
Testing for autoantibodies is a big part of diagnosing scleroderma as well as other autoimmune diseases. This involves an ANA test.
In an ANA test, a healthcare professional collects a blood sample from a vein in your arm. They then send it to a lab to be analyzed. ANAs can be detected under a microscope using a special fluorescent tag.
In addition to getting your medical history, doing a physical exam, and testing for ANAs, your healthcare professional may also want to order or perform other tests. These include:
- additional blood tests to give your doctor a better idea of your overall health and help rule out other conditions as the cause of your symptoms
- skin tests where your doctor measures your skin thickness or analyzes a skin biopsy
- nailfold capillary tests, which look for changes in your nails, a common sign of scleroderma
- CT scan, echocardiogram, or upper GI endoscopy to look at your lungs, heart, and upper digestive tract, respectively
- lung function tests to assess how well your lungs are working
A positive ANA test doesn’t mean that you absolutely have scleroderma. ANAs can be present in other autoimmune diseases as well, such as systemic lupus erythematosus and Sjogren disease.
If your doctor suspects that you have scleroderma based off of your symptoms and the results of other tests, they’ll want to see if you’re positive for scleroderma-specific autoantibodies.
This typically involves analyzing a blood sample for the presence of some of the common scleroderma antibodies like ACA, ATA, and RNA Poly III.
A positive result for one or more of these antibodies can help your doctor to confirm a diagnosis of scleroderma. It can also give them hints as to how scleroderma may affect your body.
If you receive a scleroderma diagnosis, your doctor will develop a treatment plan. Generally speaking, scleroderma treatment aims to reduce symptoms, prevent complications, and boost your overall quality of life.
The specific type of treatment you receive depends on the areas of the body affected by scleroderma. Which types of scleroderma antibodies you’re positive for can give your doctor an idea of the
Let’s look at some examples for the three predominant types of scleroderma antibodies:
- ACA: ACA is linked with limited cutaneous scleroderma. However, it’s also associated with pulmonary arterial hypertension (PAH).
- ATA: ATA is typically involved with diffuse cutaneous scleroderma. It’s also linked with interstitial lung disease. A
2023 study suggested that ATA positivity is associated with the greatest risk of major organ involvement, recommending that people with this antibody be monitored more closely. - RNA Poly III: RNA Polly III is also associated with diffuse cutaneous scleroderma. Inside the body, it’s linked with a life threatening kidney complication of scleroderma called a renal crisis. It’s also been
linked to cancer .
Some people with scleroderma have more than one type of antibody. A
The symptoms of scleroderma can depend on the type of scleroderma that you have and the part of the body that’s impacted.
Localized scleroderma typically impacts just the skin and associated tissues. It can cause patterns of skin thickening that happen in patches (morphea) or lines (linear).
Systemic sclerosis can affect the skin and can also lead to fibrosis that affects internal organs. It has two types:
- Limited cutaneous scleroderma: This develops slowly and mainly affects the skin, although it often causes problems with blood vessels, such as Reynaud phenomenon, and the upper digestive tract, such as trouble swallowing or heartburn.
- Diffuse cutaneous scleroderma: This is more severe and comes on quickly. It also affects the skin, but is also associated with damage to internal organs like the lungs, heart, and kidneys.
Scleroderma is rare and can also resemble other diseases, making it hard to diagnose. Because scleroderma may lead to serious organ damage if it’s left untreated, see your doctor if you have symptoms of scleroderma.
Visible signs of scleroderma may be what you notice first. These include new patches of skin that feel thickened and hard or noticeable changes to your nails. You may also feel as if you’ve become very sensitive to the cold.
Signs that scleroderma may be impacting one or more internal organs include:
- trouble swallowing
- heartburn
- other digestive symptoms like:
- shortness of breath
- heart palpitations
- high blood pressure
Because it can affect many different parts of the body, scleroderma is often treated by a team of different healthcare professionals. These may include rheumatologists, dermatologists, and pulmonologists.
The autoimmune effects of scleroderma can be treated with anti-inflammatory or immunosuppressant medications. Further medications can help to manage scleroderma symptoms like pain and Raynaud’s phenomenon.
Physical therapy and occupational therapy may also be beneficial for some people. Working with specialists can help to address organ-specific symptoms or damage related to scleroderma.
Learn more about treating scleroderma.
Autoantibodies are found in almost all people with scleroderma. Several types of scleroderma-specific autoantibodies have been identified.
An ANA test is used to help diagnose many autoimmune diseases. If a doctor suspects that you have scleroderma, that can test for scleroderma-specific antibodies to help make the diagnosis.
The types of scleroderma antibodies that you have can be associated with the disease you experience. Because some types of scleroderma can lead to serious organ damage, it’s important to contact a doctor if you notice signs of scleroderma.