Nouvo tès sèvi ak yon gout sèl nan san ki al nan revele istwa tout antye de enfeksyon viral

New test uses a single drop of blood to reveal entire history of viral infections


Powered by sa a ki gen tit “Nouvo tès sèvi ak yon gout sèl nan san ki al nan revele istwa tout antye de enfeksyon viral” te ekri pa Ian Egzanp editè Syans, pou Gadyen nan Jedi 4yèm nan mwa jen 2015 18.00 UTC

Chèchè yo te devlope yon tès bon mache epi rapid ki revele istwa plen yon moun nan nan enfeksyon viral ki sòti nan yon gout sèl nan san.

Egzamen sa a pèmèt doktè yo li soti yon lis viris yo sa yo ki te enfekte, oswa kontinye enfekte, pasyan menm lè yo pa te lakòz okenn sentòm evidan.

Teknoloji a vle di ke GPS te kapab ekran pasyan pou tout moun nan viris yo kapab nan enfekte moun. Li ta transfòme deteksyon an nan enfeksyon grav tankou epatit C ak VIH, ki moun ki ka pote pou ane san yo pa konnen.

"Nòmalman, lè yon doktè vle konnen si yon moun a te enfekte ak yon viris, yo gen yo devine kisa viris la se, and then look specifically for that virus,” said Stephen Elledge, who led the project at Brigham and Women’s Hospital in Boston.

“This could lead to a diagnostic where people go annually to their doctor and get their viral history recorded. It could certainly discover viral infections that are serious and that a patient didn’t know they had,"Li te di.

Nan (£16) test draws on advances in synthetic biology and rapid gene sequencing to analyse more than 1000 strains of human viruses in one pass. Jis kounye a, most tests have looked for only a single virus at a time. Elledge estimates that the latest test, called VirScan, can process 100 samples in two to three days.

The test exploits the fact that the immune system makes antibodies to fight viruses whenever the body becomes infected. These antibodies can live on in the bloodstream for years and even decades.

To develop the test, Elledge engineered batches of harmless viruses to carry bits of proteins from human viruses on their surfaces. In total, they carried proteins from more than 1000 strains of the 206 kinds of viruses known to infect people. Antibodies use these protein fragments to recognise invading viruses and launch their attacks.

When a droplet of blood from a patient is mixed with the modified viruses, any antibodies they have latch on to human virus proteins they recognise as invaders. The scientists then pull out the antibodies and identify the human viruses from the protein fragments they have stuck to.

“It’s the first time we’ve been able to look in a completely unbiased manner at what viruses are infecting people, and we can do it for all known viruses,” said Elledge. The test picks up the antibodies a person produces from vaccinations, but these can be discarded from the test results. Details are reported in the journal Syans.

In a demonstration of the technology, the team analysed blood from 569 people in the US, Lafrik di sid, Thailand and Peru. The test found that, an mwayèn, people had been infected with 10 species of viruses, though at least two people in the trial had histories of 84 infections from different kinds of viruses.

The most common infections were herpes viruses, which cause cold sores, enteroviruses that upset stomaches, influenza, and rhinoviruses that trigger common colds. Those in the US had experienced fewer infections than those in the other countries, and as expected, older people had richer viral histories than youngsters.

The test could bring about major benefits for organ transplant patients. One problem that can follow transplant surgery is the unexpected reawakening of viruses that have lurked inactive in the patient or donor for years. These viruses can return in force when the patient’s immune system is suppressed with drugs to prevent them rejecting the organ. Standard tests often fail to pick up latent viruses before surgery, but the VirScan procedure could reveal their presence and alert doctors and patients to the danger.

“This could be very valuable,” said Iwijn De Vlaminck, a biomedical engineer at Cornell University in New York, who was not involved in the study. “What this allows you to do is look into the past and measure a person’s exposure to previous infections. That has important advantages, because you can detect these infections that go to latency. You could screen blood from patients and organ donors in this very broad manner and predict potential future issues with viral reactivation.”

Scientists believe the test will also cast light on how certain viral infections can predispose people to seemingly unrelated diseases later in life. Some infections can cause permanent damage to body tissues, or alter the immune system, in ways that leave people more at risk of medical problems when they are older. Pou egzanp, infection with Epstein-Barr virus can raise the risk of cancer. But how other viruses affect long term health is far murkier. “That kind of analysis is something this really makes possible,” said Elledge. © Responsab, gadyen nouvèl & Media Limited 2010

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