Nav: Home

A new test to detect reliably an autoimmune disease

June 14, 2017

In autoimmune diseases, the immune system wrongly identifies its "enemy", and produces antibodies that attack the patient's own cells. One of these diseases, the anti-phospholipid antibody syndrome (APS), is still poorly understood, even though it can have serious consequences. APS is caused by antibodies circulating in the blood plasma that are directed against a protein, which increase the blood's tendency to form clots. This can lead to a range of vascular accidents, such as venous thromboses, strokes or repeated miscarriages. Although the prevalence of APS is very difficult to assess, it is likely to affect around 0.5% of the general population. Diagnosing the disease is a complicated affair: the test currently used has a number of problems in terms of variability, specificity and sensitivity. This situation, however, is set to change: researchers at the University of Geneva (UNIGE), Switzerland, and the Geneva University Hospitals (HUG) have succeeded in identifying the exact spot where the anti-phospholipid antibodies attach themselves. This means a more accurate and standardized diagnostic test can now be devised-- an undeniable improvement for patients. These results can be read in the journal Haematologica.

In people suffering from APS, antibodies called "anti-Β2GP1" attach themselves to elements found on the surface of certain cells, particularly those of the blood vessels and placenta. They bind themselves to receptors located on the cell membrane, generating a signal that produces the pro-inflammatory and pro-thrombotic factors that cause vascular accidents. By identifying the exact location where these antibodies bind, the research team at UNIGE and HUG have been able to clarify how they function. Karim Brandt, a researcher at the UNIGE Faculty of medicine, explains the importance of this discovery: "The current diagnostic tests use the entire protein, which reduces its specificity and leads to standardization issues.

Consequently, two tests are required at an interval of 12 weeks after a thrombotic episode or following one or more miscarriages. Our new test specifically targets this pathogenic antibody, with rapid and more accurate results."

An antibody with a rather special behaviour

The researchers managed to isolate a "motif", which is a small part of the membrane protein. Motifs are recognized by the antibody, which then binds to it, like a key in a lock. In this instance, the key can open several locks, which correspond to the proteins found on the surface of the cells and induce the pathogenic effects. And if the target protein was identified as such, it is because it is the only protein in all the human proteome to have five of these motifs; it has therefore as many potential binding points for the pathogenic antibody.

Better diagnosis and better treatment

APS is usually treated with oral anticoagulants such as low-molecular-weight heparin and aspirin, long-term treatments that are not without side effects, and that must be used with caution by pregnant women. Moreover, treatment becomes very burdensome in patients suffering from the most severe form of the disease, called "catastrophic APS". As Karim Brandt is keen to stress, the researchers are also focusing their working in this direction: "Our breakthrough could also give rise to a targeted treatment that would neutralize specific pathogenic antibodies, reducing not just their actions but also the side effects associated with the current treatment. It would involve injecting the protein motif we have identified into a patient's circulatory system so that it explicitly binds itself to the pathogenic antibody and prevents it from causing harm."

For the time being, the diagnostic test needs to be optimized for prototypes to be developed. To ensure its validity, the researchers will reanalyze hundreds of samples already tested with the old method and compare results.
-end-


Université de Genève

Related Protein Articles:

Hi-res view of protein complex shows how it breaks up protein tangles
A new, high-resolution view of the structure of Hsp104 (heat shock protein 104), a natural yeast protein nanomachine with six subunits, may show news ways to dismantle harmful protein clumps in disease.
Breaking the protein-DNA bond
A new Northwestern University study finds that unbound proteins in a cell break up protein-DNA bonds as they compete for the single-binding site.
FASEB Science Research Conference: Protein Kinases and Protein Phosphorylation
This conference focuses on the biology of protein kinases and phosphorylation signaling.
Largest resource of human protein-protein interactions can help interpret genomic data
An international research team has developed the largest database of protein-to-protein interaction networks, a resource that can illuminate how numerous disease-associated genes contribute to disease development and progression.
STAT2: Much more than an antiviral protein
A protein known for guarding against viral infections leads a double life, new research shows, and can interfere with cell growth and the defense against parasites.
A protein makes the difference
It is well-established knowledge that blood vessels foster the growth of tumors.
Nuclear protein causes neuroblastoma to become more aggressive
Aggressive forms of neuroblastoma contain a specific protein in their cells' nuclei that is not found in the nuclei of more benign forms of the cancer, and the discovery, made through research from the University of Rochester Medical Center, could lead to new forms of targeted therapy.
How a protein could become the next big sweetener
High-fructose corn syrup and sugar are on the outs with calorie-wary consumers.
High animal protein intake associated with higher, plant protein with lower mortality rate
The largest study to examine the effects of different sources of dietary protein found that a high intake of proteins from animal sources -- particularly processed and unprocessed red meats -- was associated with a higher mortality rate, while a high intake of protein from plant sources was associated with a lower risk of death.
Protein in, ammonia out
A recent study has compiled and analyzed data from 25 previous studies.

Related Protein Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".