Anti-SSA Test (anti-Ro): Know Your Labs
What is the anti-SSA test?
Remember… Knowledge is Power!
So, let’s talk about anti-SSA (also called anti-Ro).
Anti-SSA antibody: Also called Anti-Sjögren’s Syndrome A, Sjögren’s Anti-SS-A, Ro Antibody
Why is anti-SSA also called anti-Ro?
Anti-SSA and anti-SSB antibodies were first discovered in 1961 in people who had Sjögren’s syndrome. This systemic autoimmune disorder attacks the body’s moisture-producing glands, commonly causing dry eyes and dry mouth. The medical terms for them are “Sjögren’s syndrome-A” and “Sjögren’s syndrome-B” antibodies (or SSA and SSB for short). In 1969, another laboratory described antibodies in people who had lupus and named them anti-Ro and anti-La. “Ro” and “La” were the first two letters of the last names of the lupus patients in whom the antibodies were initially found (Robert and Lane respectively, according to Dubois’ Lupus 9th edition). Researchers later showed that anti-SSA was the same as anti-Ro and that anti-SSB was the same as anti-La. These terms are now interchangeable, with anti-SSA meaning the same thing as anti-Ro and anti-SSB meaning the same thing as anti-La.
How often does it occur?
Anti-SSA is more commonly positive in SLE patients than anti-SSB. SSA is positive in 20% to 60% of people who have SLE (depending on the patient population and the laboratory method used to detect the antibodies). Anywhere from 75% to 95% of people who have Sjögren’s syndrome are positive for this antibody. It can be present in any of the systemic autoimmune diseases and nonautoimmune conditions.
Some things may occur more often in people positive for anti-SSA antibodies:
IMPORTANT NOTE: From the list above, the most important ones are sun-sensitive rash and Sjögren’s. Most do not develop the other problems, but are listed for your knowledge. Your doctor will monitor your liver enzymes and blood counts (hopefully every 3 months) and make sure to let your doctor know if you get chest pain, shortness of breath, bruising, rash, dry mouth or dry eyes.
Anti-SSA positive patients should particularly avoid ultraviolet light and become UV protection fanatics. Please download and follow my UV protection handout from this page:
ANA-negative SLE patients and anti-SSA
Although it is rare, some people who have SLE and are negative for ANA are positive for SSA antibody. If someone is thought to have SLE, but their ANA is negative, doctors should check for SSA antibodies. A newer ANA test, called “HEp-2000 ANA” (by a laboratory called Immuno Concepts in Sacramento, California), may be better at showing ANA positivity in these patients who are SSA antibody positive.
Anti-SSA can become positive years before SLE occurs
SSA antibody can be positive in someone many years before they develop lupus or Sjögren’s. It is one of the earliest antibodies to appear in many patients. This was figured out from blood samples of Army soldiers at the old Walter Reed Army Medical Center (Washington, DC) where I did my rheumatology fellowship.
It is essential that people found to have a positive SSA antibody (but not have evidence of having lupus, Sjögren’s, or any associated disease) be checked regularly by a doctor. I recommend that people in this situation learn what the symptoms of lupus and Sjögren’s are, and if any occur, to see a rheumatologist right away. Also, it is a good idea to see a rheumatologist regularly (such as once or twice a year) to have a proper physical examination and labs done. SLE can be potentially diagnosed by blood work (such as finding low blood counts or protein in the urine), yet the person may feel perfectly fine. The faster a proper diagnosis is made, the better the person usually does. Of course, someone who is SSA antibody positive may never develop any disease with it, but it better to be safe. I’d also recommend that someone in this category (antibody positive but no disease) avoid all potential triggers that may cause lupus (see table 3.1).
Important pregnancy information about anti-SSA:
However, suppose a mother with SSA antibody has one child with neonatal lupus. In that case, her chances of each subsequent baby having neonatal lupus are approximately 20%.
Source of text:
from “The Lupus Encyclopedia” preliminary write up for the upcoming 2nd edition, by Don Thomas, MD and Johns Hopkins University Press
References for the above can be found under chapter 4 here:
Photo credit (1st photo of lab test HeP immunofluorescence of anti-SSA test = from www.wikipedia.com article on Anti-SSA/anti-Ro antibodies, photo by Simon Caulton