Stories about: immunology

Link found between chronic inflammation, autoimmune disorders and “false alarms”

Viruses (pictured here) have a genetic signature that a receptor called MDA5 recognizes. But when MDA5 confuses the body's own genetic material with that of a virus, disease ensues.
Viruses have a genetic signature that a human receptor called MDA5 recognizes, causing the immune system to attack. But when MDA5 confuses the body’s own genetic material for that of a virus, disease ensues.

The human body’s innate immune system employs a variety of “sensors” for identifying foreign invaders such as viruses. One such viral sensor is a receptor called MDA5, found in every cell of the body.

Inside each cell, MDA5 constantly scans genetic material, checking if it’s native to the body or not. As soon as MDA5 identifies the genetic signature of a viral invader, it trips a system-wide alarm, triggering a cascade of immune activity to neutralize the threat.

But if a genetic mutation to MDA5 causes it to confuse some of the body’s own genetic material for being foreign, “false alarms” can lead to unchecked inflammation and disease. Scientists from Boston Children’s Hospital have discovered a new link between MDA5’s ability to discriminate between “self” and “non-self” genetic material — called RNA duplexes — and a spectrum of autoimmune disorders.

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Science and medicine in 2018: What’s the forecast?

2018 predictions for biomedicine

Vector consulted its many informants to find out which way the wind will blow in 2018. Here are their predictions for what to expect in genetics, stem cell research, immunology and more.

GENETICS

Gene-based therapies mature

We will continue to see successes in 2018 reflecting the maturation of gene therapy as a viable, generalizable platform for curing many rare diseases. Also, we will see exciting new applications of other maturing platforms, like CRISPR/Cas9 gene editing and oligonucleotide therapies for neurologic diseases, building on the success of nusinersen for spinal muscular atrophy.

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How do cells release IL-1? The answer packs a punch, and could enable better vaccines

In hyperactivated immune cells, gasdermin D punches holes in the cell membrane that let IL-1 out — without killing the cell.

Interleukin-1 (IL-1), first described in 1984, is the original, highly potent member of the large family of cellular signaling molecules called cytokines that regulate immune responses and inflammation. It’s a key part of our immune response to infections, and also plays a role in autoimmune and inflammatory diseases. Several widely used anti-inflammatory drugs, such as anakinra, block IL-1 to treat rheumatoid arthritis, systemic inflammatory diseases, gout and atherosclerosis. IL-1 is also a target of interest in Alzheimer’s disease.

Yet until now, no one knew how IL-1 gets released by our immune cells.

“Most proteins have a secretion signal that causes them to leave the cell,” says Jonathan Kagan, PhD, an immunology researcher in Boston Children’s Hospital’s Division of Gastroenterology. “IL-1 doesn’t have that signal. Many people have championed the idea that IL-1 is passively released from dead cells: you just die and dump everything outside.”

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Breastfeeding protects against food allergy: We have evidence

Mother breastfeeding her baby. Is she helping her child avoid food allergy?

Eating allergenic foods during pregnancy can protect your child from food allergies, especially if you breastfeed, suggests new research. The findings, in a mouse model of allergy, underscore recent advice that pregnant or nursing mothers not avoid allergenic foods like eggs and peanuts.

The study is the first controlled investigation to demonstrate protection against food allergy from breast milk, while also pointing to a biological mechanism for inducing food tolerance. It was published online today in the Journal of Experimental Medicine.

“Whether mothers should eat allergenic foods during pregnancy or avoid them has been controversial,” says Michiko Oyoshi, PhD, of Boston Children’s Division of Allergy and Immunology, who led the study in collaboration with Richard Blumberg, MD, of Brigham and Women’s Hospital, her co-senior author.

“Different studies have found different results, in part because it’s hard in human studies to know when mothers and babies first encountered a specific food,” says Oyoshi. “But in a mouse model, we can control exposure to food.”

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Pre-treated blood stem cells reverse type 1 diabetes in mice

autoimmune attack in type 1 diabetes
In type 1 diabetes, autoreactive T-cells (like the one in yellow) attack insulin-producing beta cells in the pancreas. What if blood stem cells could be taught to neutralize them? (Image: Andrea Panigada)

Type 1 diabetes is caused by an immune attack on the pancreatic beta cells that produce insulin. To curb the attack, some researchers have tried rebooting patients’ immune systems with an autologous bone-marrow transplant, infusing them with their own blood stem cells. But this method has had only partial success.

New research in today’s Science Translational Medicine suggests a reason why.

“We found that in diabetes, blood stem cells are defective, promoting inflammation and possibly leading to the onset of disease,” says Paolo Fiorina, MD, PhD, of Boston Children’s Hospital, senior investigator on the study.

But they also found that the defect can be fixed — by pre-treating the blood stem cells with small molecules or with gene therapy, to get them to make more of a protein called PD-L1.

In experiments, the treated stem cells homed to the pancreas and reversed hyperglycemia in diabetic mice, curing almost all of them of diabetes in the short term. One third maintained normal blood sugar levels for the duration of their lives.

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Microbial murder mystery solved

Bacteria, pictured in Petri dish culture here, can become resistant to antibiotics - but not killer cells. Why? New research from Boston Children's Hospital helps solve this microbial murder mystery.Immune cells called “killer cells” target bacteria invading the body’s cells, but how do they do this so effectively? Bacteria can quickly evolve resistance against antibiotics, yet it seems they have not so readily been able to evade killer cells. This has caused researchers to become interested in finding out the exact mechanism that killer cells use to destroy bacterial invaders.

Although one way that killer cells can trigger bacterial death is by inflicting oxidative damage, it has not yet been at all understood how killer cells destroy bacteria in environments without oxygen.

Now, for the first time, researchers have caught killer cells red-handed in the act of microbial murder

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Finding what fuels the “runaway train” of autoimmune diseases

Competing B cells, pictured here, produce autoantibodies that contribute to autoimmune disease
Natural selection on a small scale: Immune cells called B cells battle each other to produce the best antibody. Here, green represents the B cells that are producing the “winning” antibody, which stamp out competing B cells (other colors). Credit: Carroll lab

A newly-unveiled discovery, four years in the making, could change the way we look at autoimmune diseases and our understanding of how and why immune cells begin to attack different tissues in the body.

“Once your body’s tolerance for its own tissues is lost, the chain reaction is like a runaway train,” says Michael Carroll, PhD, of Boston Children’s Hospital and Harvard Medical School (HMS). “The immune response against your own body’s proteins, or antigens, looks exactly like it’s responding to a foreign pathogen.”

A team led by Carroll has spent years investigating mouse models of lupus to better understand the ins and outs of autoimmune diseases. Its latest findings, published in Cell, reveal that rogue B cells — immune cells that produce antibodies and program the immune system to attack certain antigens — can trigger an “override” that launches the body into an autoimmune attack. Adding insult to injury, B cells’ immune targeting instructions can rapidly expand to order an attack on additional tissue types within the body.

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A surprising new link between inflammation and mental illness — and a potential drug to protect the brain

A synapse being attacked by microglia, which causes neuropsychiatric symptoms in lupus
In the brain, a synapse (red – see diagonal “spine” across center of photo) is seen being wrapped around and attacked by immune cells called microglia (green), leading to synapse loss. Credit: Carroll lab / Boston Children’s Hospital

Up to 75 percent of patients with systemic lupus erythematosus — an incurable autoimmune disease commonly known as “lupus” —  experience neuropsychiatric symptoms.  But so far, our understanding of the mechanisms underlying lupus’s effects on the brain has remained murky.

“In general, lupus patients commonly have a broad range of neuropsychiatric symptoms, including anxiety, depression, headaches, seizures, even psychosis,” says Allison Bialas, PhD, a research fellow working in the lab of Michael Carroll, PhD, of Boston Children’s Hospital. “But their cause has not been clear — for a long time it wasn’t even appreciated that these were symptoms of the disease.”

Collectively, lupus’ neuropsychatric symptoms are known as central nervous system (CNS) lupus. Their cause has been unclear until now.

Perhaps, Bialas thought, changes in the immune systems of lupus patients were directly causing these symptoms from a pathological standpoint. Working with Carroll and other members of his lab, Bialas started out with a simple question, and soon, made a surprising finding – one that points to a potential new drug for protecting the brain from the neuropsychiatric effects of lupus and other diseases. The team has published its findings in Nature.

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Effective vaccination of newborns: Getting closer to the dream

newborn vaccines global health

In many parts of the world, babies have just one chance to be vaccinated: when they’re born. Unfortunately, newborns’ young immune systems don’t respond well to most vaccines. That’s why, in the U.S., most immunizations start at two months of age.

Currently, only BCG, polio vaccine and hepatitis B vaccines work in newborns, and the last two require multiple doses. But new research raises the possibility of one-shot vaccinations at birth — with huge implications for reducing infant mortality.

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News Note: Steroids could be counter-productive in severe asthma

severe asthma
Nine years old kid with allergic asthma, inhaling his medication through spacer while looking at with his wide opened eyes perhaps he is getting energy boost

Some 10 to 15 percent of people with asthma have severe disease that medications can’t control. A deep-dive multicenter study finds differences in these patients’ immune systems that may explain why increased dosages of corticosteroids don’t help — and could lead to steroids doing more harm than good. Findings appear online this week in Science Immunology.

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