Research shows improvements in tests detecting the SS-B antibody.

The following article is reprinted from the National Institutes of Health News website.

For the thousands of Americans who will be evaluated this year for the autoimmune disorder primary Sjögren's syndrome, their doctors will likely test for two antibodies that are often associated with the condition. The problem is today's standard blood tests detect the more strongly associated antibody, called SSB, only about half the time, making the meaning of a negative result uncertain.

But these numbers could one day improve. Scientists at the National Institute of Dental and Craniofacial Research (NIDCR), part of the National Institutes of Health, report online in the journal Autoimmunity that a rapid, automated test now under development called LIPS identified the SSB antibody correctly three out of four times and with perfect accuracy. It also detected a second antibody, SSA, about as well as today's standard assays in the group's initial study of 82 people, 57 of whom had well-characterized primary Sjögren's syndrome.

"This is just step one in our work to improve antibody detection for Sjögren's syndrome," said Peter Burbelo, Ph.D., lead author on the paper and a scientist at NIDCR. “With further refinements, the percentages will only get better."

Burbelo and colleagues also reported using LIPS to profile additional antibodies of interest that may be related to other largely unrecognized manifestations of the syndrome. These first-pass antibody profiles have the potential to help scientists define for the first time a range of clinical subtypes of primary Sjögren's, which could greatly improve diagnoses and possibly better target treatment.

Primary Sjögren's syndrome is a chronic autoimmune disorder that affects about 4 million Americans, 90 percent of whom are women. Scientists have long thought the syndrome is triggered when white blood cells mistakenly attack the body's moisture-producing glands, typically causing chronic dry mouth, dry eyes, and arthritis.

But other Sjögren's-related health problems continue to be reported in the medical literature, including lymphoma, thyroid dysfunction, painful peripheral neuropathy, and gastrointestinal problems. These seemingly phantom symptoms remain poorly defined, diagnostically controversial, and suggest a more systemic and yet-to-be-defined underlying pathology.

That's where LIPS enters the picture. Short for luciferase immunoprecipitation technology, LIPS is a traditional bait-and-bind diagnostic assay. The bait is any recombinant laboratory-made antigen, or segment of a protein known to elicit an antibody response, that is then fused to an enzyme similar to the light-producing luciferase that produces the flash in fireflies.

According to Burbelo, this hybrid antigen is incubated in solution with a drop of a person's serum. If the antibody of interest is present, it will bind to the bait. Thereafter, the entire antibody-antigen complex attaches to small beads that are then measured by its firefly-like light emission. The greater the intensity of the light flash, the more target antibody there is bound to the antigen.

What makes LIPS different from other antibody tests is its extreme sensitivity, or ability to correctly detect an antibody of interest. Burbelo said this stems from selecting mammalian cells and its biological machinery as the recombinant cloning vector to make the antigens. They more closely resemble human cells than the non-mammalian sources typically used today to make test antigens, such as the bacterium E. coli.

"Antibodies must see the natural three-dimensional shape of an antigen to recognize it," said Burbelo. "With today's tests, the assumption is an antigen's three-dimensional shape will be retained once it's produced and affixed to plastic. But typically that's not the case. Antibodies will recognize a stretch of amino acids here and maybe there. They won't see other pieces of the protein that have degraded and lost their natural conformations."

"With LIPS, more of the three-dimensional shape is retained, and that heightens the sensitivity," he continued. "For example, an ELISA [Enzyme-Linked ImmunoSorbent Assay] typically has a dynamic range of between 5 and 15,000 units of signal. A unit of signal is the measure of light intensity. In other words, how bright is the test’s green or red signal? With LIPS, we see samples that range from zero to sometimes over a million units of signal."

This zero-to-million diagnostic window allows Burbelo and colleagues to more objectively measure any antibody response associated with an autoimmune disorder. It also suggests LIPS may have the potential to detect most developing autoimmune disorders before they become symptomatic, more closely monitor the ups and downs of a patient's antibody counts over time, and track the immunological outcome of an autoimmune treatment.

To date, Burbelo and colleagues have published intriguing data involving LIPS and a range of autoimmune conditions, from type I diabetes to herpes simplex virus. In the current study, they began by applying their new tool to the Sjögren's-associated antibodies, SSA and SSB. But they did so with a diagnostic twist.

"Traditionally, the SSA antigen consists of two proteins — Ro52 and Ro60 — that are conjoined and anchored on the plastic diagnostic assays," said Mike Iadarola, Ph.D., an NIDCR scientist and senior author on the study. "We teased apart the two proteins to present their full three-dimensional shape and were able to measure the antibody response to each separately."

The group found that 42 of the study's 57 previously diagnosed Sjögren's patients had antibody reactions against a segment of the Ro52 antigen that does not elicit a response in today's ELISA tests, a sign of the LIPS assay's greater sensitivity. Overall, LIPS detected antibody responses against each protein in about 60 percent of patients, roughly equal to an ELISA, but with a far greater dynamic range and perfect specificity.

The scientists then decided to test for other conditions not traditionally linked to Sjögren's syndrome but that occasionally — and bewilderingly — have been reported in some patients. "We hypothesized that if we made antigens for the thyroid, stomach, and peripheral nervous system, LIPS could pick out the subset of patients with antibodies against these tissues," said Iadarola.

And it did. The scientists found 14 percent of their Sjögren's patients had antibodies against the thyroid antigen, 16 percent had antibodies against an antigen associated with autoimmune gastritis, and four percent had antibodies linked to an autoimmune attack of the eye's peripheral nerve.

These findings suggest that LIPS may be used as a substitute for more invasive and expensive procedures typically used to diagnose these peripheral conditions. "Again, this study is just a start," said Burbelo. "All of these tests can be performed on the automated robotic machine in my laboratory, and we can do thousands a day. There's more data to come."

The paper is titled, "Sensitive and robust luminescent profiling of anti-La and other autoantibodies in Sjögren's syndrome." The authors are Peter D. Burbelo, Hannah P. Leahy, Alexandra T. Issa, Sandra Groot, James N. Baraniuk, Nikolay P. Nikolov, Gabor G. Illei, and Michael J. Iadarola. The paper was published online on August 3, 2009.

The National Institute of Dental and Craniofacial Research (NIDCR) is the Nation’s leading funder of research on oral, dental, and craniofacial health.

The National Institutes of Health (NIH) — The Nation's Medical Research Agency — includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

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Steven Taylor, CEO of the Sjogren's Syndrome Foundation, keeps busy year round helping to raise awareness about Sjogren's. Now you can see just what he and the Foundation are up to by following him on Twitter!

Visit his page at twitter.com/SjogrensCEO to learn how Steve is fighting daily to make Sjogren's a household name.

Starting in February 2009, the Sjögren’s Syndrome Foundation began a nationwide mailing to reach every rheumatologist in the United States registered with the American College of Rheumatology (ACR).

As many Sjögren’s patients know too well, much of the medical community is vastly underinformed about the latest Sjögren’s news and treatments. That is why we have partnered with ACR to help raise awareness with rheumatologists in the United States.

Over 9,000 rheumatologists across the country will receive a letter informing them about the activities of the Foundation, noting our committment to research and advocacy. In addition, enclosed with the letter is a copy of the latest issue of the Sjögren’s Quarterly — our professional newsletter — as well as a copy of our What is Sjögren’s Syndrome? brochure. Both the Quarterly and all of our brochures are available free-of-charge to any healthcare professionals in the United States.

Since beginning the mailing, we have been inundated with replies from doctors asking ot receive more materials and be subscribed to the Sjögren’s Quarterly

So at your next doctor's visit, ask your rheumatologist if they have received this letter from the SSF. And if not, make sure they contact the Foundation office to receive their complimentary educational materials and sign up for our professional newsletter.

The SSF has joined with the National Health Council and its members in putting patients first!

The lack of effective health care coverage is one of the most important issues facing our nation. Nearly 50 million Americans have no coverage at all. Many more have coverage that does not provide for their basic health and longterm care needs. The problem is especially acute for Americans with a chronic disease or disability – like Sjögren’s patients and others represented by the National Health Council.

That is why we have joined the National Health Council's Campaign to Put Patients First.

With the National Health Council, we support health care that

  • Covers everyone
  • Curbs costs responsibly
  • Abolishes exclusions for pre-existing conditions
  • Eliminates lifetime caps
  • Ensures long-term and end-of-life care

On behalf of the more than 133 million people with chronic diseases and disabilities and their family caregivers, we urge the Administration and Congress to enact specific solutions that guarantee effective and affordable health and long-term care coverage for all Americans.

Click here to sign the petition, and add your voice to the group that has chosen to Put Patients First.

 

A note about Sjögren’s Syndrome Awareness Month from the CEO of the Sjögren’s Syndrome Foundation:

April is Sjögren’s Syndrome Awareness Month and each year the Foundation chooses a theme and focus for our national awareness campaign. This year, our theme is Research – Our Hope for the Future.

The awareness campaign is simple: we are asking each member of the Foundation to consider mailing informational letters we provide you to six of your friends and/or family members. By doing this, you will be helping to increase knowledge about Sjögren’s syndrome, as well as helping the Foundation to make Sjögren’s syndrome a household name.

If you are already a member of the Foundation, then in April you will receive a Research – Our Hope for the Future kit in the mail. This kit will contain six letters for you to send to family and friends that will educate them on Sjögren’s syndrome, and focus on Sjögren’s syndrome research. It will also ask the recipient to consider making a gift to the Sjögren’s Syndrome Foundation. But remember, whether or not they give a gift, the most important part is that we are educating people on Sjögren’s syndrome.

What is unique about this year’s awareness campaign is that it is focusing on research and the need for more funding. With this in mind, and as a way to recognize your efforts in helping us, we are awarding one of you a 2009 Student Research Fellowship named in your honor! (i.e. “The Mary Smith 2009 Student Fellowship”)

All you have to do is mail all six letters and then send us the Summary Report letting us know that you helped to increase awareness, and you will have a chance at winning a grant named in your honor. Detailed information and instructions for entry will be included in the awareness kit you will receive in early April.

If you have any questions about our campaign please do not hesitate to contact the Foundation office at 800- 475-6473. All members of the SSF should receive their kit in the mail. If you have not received your kit by the beginning of April, or if you are not a member but would like to help raise awareness, contact the Foundation office.

Good luck and remember that it is critical all of us help spread the word about Sjögren’s syndrome. Together, we will make Sjögren’s a household name!

Sincerely,

Steven Taylore's signature
Steven Taylor
Chief Executive Officer