Page 22 - HOH_Neat

A12 HEALTH
Thursday 1 OcTOber 2020
Mild to severe: Immune system holds clues to virus reaction

for hospitalization, giving Herold's
team the opportunity to compare
60 adults and 65 children and
teens at New York's Montefiore
Health System.
The children produced much high-
er levels of certain cytokines that
are among the innate immune sys-
tem's first responders. When the im-
mune system's next stage kicked in,
both adults and children made an-
tibodies targeting the coronavirus.
Here's the rub: The adults' adaptive
immune response was more the
type that can trigger an inflamma-
tory overreaction.
The findings suggest kids' early ro-
bust reaction lets their immune sys-
tem get ahead of the virus, mak-
ing an overreaction less likely "and
that's protecting them," Herold
said.
ANY PREEXISTING IMMUNITY?
The coronavirus that causes COV-
ID-19 is new to humans. But Sette's
team studied blood samples that
were stored in freezers before the
pandemic and found some har-
This electron microscope image made available and color-enhanced by the National Institute of Allergy and Infectious bored memory T cells that recog-
Diseases Integrated Research Facility in Fort Detrick, Md., in 2020, shows Novel Coronavirus SARS-CoV-2 virus particles, nized a tiny portion of the new virus
orange, isolated from a patient. in laboratory tests.
Associated Press "You can actually tell that this is an
By LAURAN NEERGAARD and CAN- they were to begin with and how But new research shows those cru- experienced T cell. This has seen
DICE CHOI much of the virus — the "dose" — cial molecules were essentially ab- combat before," Sette said. Re-
Associated Press they were exposed to. sent in a subset of people with se- searchers in Germany, Britain and
One of COVID-19's scariest myster- "Infection and what happens after vere COVID-19. other countries have made similar
ies is why some people are mildly infection is a very dynamic thing," An international project uncovered findings.
ill or have no symptoms and oth- said Alessandro Sette, a researcher two reasons. In blood from nearly The new coronavirus has cousins
ers rapidly die — and scientists are at the La Jolla Institute for Immunol- 1,000 severe COVID-19 patients, that cause as many as 30% of com-
starting to unravel why. ogy in San Diego, who is studying researchers found 1 in 10 had what mon colds, so researchers believe
An international team of research- yet another piece of the immune are called auto-antibodies — an- those T cells could be remnants
ers found that in some people with response. tibodies that mistakenly attack from past colds.
severe COVID-19, the body goes IMMUNE PRIMER those needed virus fighters. Espe- But despite the speculation, "we
rogue and attacks one of its own There are two main arms of the im- cially surprising, autoimmune dis- don't know yet" that having those T
key immune defenses instead of mune system. Innate immunity is orders tend to be more common cells makes any difference in who
fighting the coronavirus. Most were the body's first line of defense. As in women — but 95% of these CO- gets seriously sick with COVID-19,
men, helping to explain why the vi- soon as the body detects a for- VID-19 patients were men. noted Rory de Vries, co-author of
rus is hitting men harder than wom- eign intruder, key molecules, such The researchers didn't find the a study in the Netherlands that also
en. as interferons and inflammation- damaging molecules in patients found such T cells in old blood.
And separate research suggests causing cytokines, launch a wide- with mild or asymptomatic CO- All these findings beg for a deeper
that children fare better than adults ranging attack. VID-19. understanding of the myriad ways
thanks to robust "first responder" im- Innate immune cells also alert the In another 660 severely ill patients, some people can be more suscep-
mune cells that wane with age. slower-acting "adaptive" arm of the same team found 3.5% had tible than others.
They're the latest in a list of studies the immune system, the germ-spe- gene mutations that didn't pro- "We need to look quite broadly
uncovering multiple features of the cific sharpshooters, to gear up. B duce Type I interferons. and not jump into premature con-
immune system's intricate cascade cells start producing virus-fighting Each of those silent vulnerabilities clusions about any one particular
that can tip the scales between a antibodies, the proteins getting was enough to tip the balance in facet of the immune system," said
good or bad outcome. Next up: so much attention in the vaccine favor of the virus early on, said Dr. Stanford University immunologist
Figuring out if all these new clues hunt. Jean-Laurent Casanova, an infec- Bali Pulendran. He also has found
might offer much-needed ways to But antibodies aren't the whole sto- tious disease geneticist at Rock- some innate immune cells "in a
intervene. ry. Adaptive immunity's many oth- efeller University in New York, who state of hibernation" in seriously ill
"We have the knowledge and ca- er ingredients include "killer" T cells co-leads the COVID Human Ge- adults and next is looking for differ-
pability of really boosting many that destroy virus-infected cells — netic Effort. ences before and after people get
aspects of the immune system. and "memory" T and B cells that re- Certain interferons are used as sick.
But we need to not use the sledge member an infection so they spring medicines and are under study as But, "it's not just all about the im-
hammer," cautioned Dr. Betsy Her- into action quicker if they encoun- a possible COVID-19 treatment; mune system," cautioned Dr. Anita
old of New York's Albert Einstein ter that germ again. the auto-antibody discovery adds McElroy, a viral immunity expert at
College of Medicine, who co-au- A MISSING PIECE another factor to consider. the University of Pittsburgh Medical
thored the child study. Usually when a virus invades a cell, KIDS' IMMUNITY REVS FAST Center who's closely watching the
Adding to the complexity, people's proteins called Type I interferons It's not clear why children appear research. A way to tell in advance
wildly varying reactions also reflect spring into action, defending the less at risk from COVID-19. But oc- who's most at risk? "We're a long,
other factors, such as how healthy cell by interfering with viral growth. casionally they're sick enough long way from that."q