COVID-triggered autoimmunity may be mostly temporary

In people with severe COVID-19, the immune system goes temporarily berserk and generates a wide variety of autoantibodies: proteins that are tools for defense, but turned against the body’s own tissues.

During acute infection, COVID-19 patients’ immune systems resemble those of people with diseases such as lupus or rheumatoid arthritis. However, after the storm passes, the autoantibodies decay and are mostly removed from the body over time, according to a study of a small number of patients who were hospitalized and then recovered.

In a preprint posted on medRxiv, Emory immunologists provide a view of the spectrum of what COVID-generated autoantibodies react against, both during acute infection and later. Note: the results have not yet been published in a peer-reviewed journal.

The findings on COVID-19-triggered autoimmunity may have implications for both the treatment of acute infection and for long-haulers, in whom autoantibodies are suspected of contributing to persistent symptoms such as fatigue, skin rashes and joint pain.

During acute infection, testing for autoantibodies may enable identification of some patients who need early intervention to head off problems later. In addition, attenuation of autoantibody activity by giving intravenous immunoglobulin (IVIG) – an approach that has been tested on a small scale — may help resolve persistent symptoms, the Emory investigators suggest.

Researchers led by Ignacio Sanz, MD and Frances Eun-Hyung Lee, MD, isolated thousands of antibody-secreting cells from 7 COVID-19 patients who were in ICUs at Emory hospitals. They also looked for markers of autoimmunity in a larger group of 52 COVID-19 ICU patients.

Posted on August 24, 2021 by Quinn Eastman in Uncategorized Leave a comment

More evidence for autoantibodies in severe COVID-19

A recent paper from Emory pathologist Cheryl Maier and colleagues provides more evidence for autoantibodies in critically ill COVID-19 patients. Autoantibodies are signs that the immune system attacking the body itself, and are features of diseases such as lupus and rheumatoid arthritis. They have been proposed as an explanation for the severity of some acute COVID-19 cases, as well as continued symptoms in long COVID.

Generally, antibodies are a good thing, and a major goal of COVID-19 vaccination is to drive the immune system to generate protective antibodies against the coronavirus. With autoantibodies and COVID, the idea is that intense inflammation coming from viral infection is causing immune cells to become confused. Not every COVID-19 patient’s immune system goes off the rails, but the train wreck seems to happen more often in COVID-19.

Last year, immunologist Ignacio Sanz’s lab at Emory demonstrated that patients with severe COVID-19 display signs of immune dysregulation similar to those seen in lupus. A follow-up preprint found the suspected autoantibodies, and several other labs have observed autoantibodies in COVID-19 that may be sabotaging antiviral responses or perturbing blood clotting. Now, an active topic of investigation is whether the autoantibodies last longer or don’t diminish as quickly in long COVID. Stay tuned.

This image has an empty alt attribute; its file name is MaierC.jpg — Cheryl Maier, MD, PhD

However, in the current paper in Cell Reports Medicine, autoantibodies were also found in most control samples from intensive care unit patients with pneumonia or sepsis, who are experiencing a state of systemic inflammation comparable to severe COVID-19.

“It’s a reminder that autoantibodies are not necessarily unique to COVID,” Maier says. “They may be more dramatic in COVID, but we see autoantibodies associated with other severe diseases too.”

Maier is medical director for Emory’s Special Coagulation Laboratory, and her team came to the autoimmunity question from a side angle. They were investigating blood clots and hyperviscosity in COVID-19 patients, and wanted to check whether high concentrations of antibodies might be an explanation. Antibodies are proteins, after all, and if someone’s blood is full of them, they thicken it.

Posted on June 3, 2021 by Quinn Eastman in Immunology Leave a comment

Steer microglia toward the angels – with a drug based on sea anemone venom

Researchers interested in Alzheimer’s and other neurodegenerative diseases are focusing their attention on microglia, cells that are part of the immune system in the brain.

Author Donna Jackson Nakazawa titled her recent book on microglia “The Angel and the Assassin,” based on the cells’ dual nature; they can be benign or malevolent, either supporting neuronal health or driving harmful inflammation. Microglia resemble macrophages in their dual nature, but microglia are renewed within the brain, unlike macrophages, which are white blood cells that infiltrate into the brain from outside.

At Emory, neurologist Srikant Rangaraju’s lab recently published a paper in PNAS on a promising drug target on microglia: Kv1.3 potassium channels. Overall, the results strengthen the case for targeting Kv1.3 potassium channels as a therapeutic approach for Alzheimer’s.

Kv1.3 potassium channels have also been investigated as potential therapeutic targets in autoimmune disorders, since they are expressed on T cells as well as microglia. The peptide dalazatide, based on a toxin from the venom of the Caribbean sea anemone Stichodactyla helianthus, is being developed by the Ohio-based startup TEKv Therapeutics. The original venom peptide needed to be modified to make it more selective toward the right potassium channels – more about that here.

Kv1.3 potassium channels are potential therapeutic targets in autoimmune disorders and Alzheimer’s — blockable with peptides based on venom of the sea anemone *Stichodactyla helianthus*

It appears that Kv1.3 levels on microglia increase in response to exposure to amyloid-beta, the toxic protein fragment that accumulates in the brain in Alzheimer’s, and Kv1.3 may be an indicator that microglia are turning to the malevolent side.

In the Emory paper, researchers showed that Kv1.3 potassium channels are present on a subset of microglia isolated from Alzheimer’s patients’ brains. They also used bone marrow transplant experiments to show that the immune cells in mouse brain that express Kv1.3 channels are microglia (internal brain origin), not macrophages (transplantable w/ bone marrow).

Posted on March 16, 2021 by Quinn Eastman in Immunology, Neuro Leave a comment

Deep brain stimulation for narcolepsy: proof of concept in mouse model

Emory neurosurgeon Jon Willie and colleagues recently published a paper on deep brain stimulation in a mouse model of narcolepsy with cataplexy. Nobody has ever tried treating narcolepsy in humans with deep brain stimulation (DBS), and the approach is still at the “proof of concept” stage, Willie says.

People with the “classic” type 1 form of narcolepsy have persistent daytime sleepiness and disrupted nighttime sleep, along with cataplexy (a loss of muscle tone in response to emotions), sleep paralysis and vivid dream-hallucinations that bleed into waking time. If untreated, narcolepsy can profoundly interfere with someone’s life. However, the symptoms can often be effectively, if incompletely, managed with medications. That’s why one question has to be: would DBS, implemented through brain surgery, be appropriate?

The room where it happens. Sandwiched between the thalamus and the pituitary, the hypothalamus is home to several distinct bundles of neurons that regulate appetite, heart rate, blood pressure and sweating, as well as sleep and wake. It’s as if in your house or apartment, the thermostat, alarm clock and fuse box were next to each other.

Emory audiences may be familiar with DBS as a treatment for conditions such as depression or Parkinson’s disease, because of the pioneering roles played by investigators such as Helen Mayberg and Mahlon DeLong. Depression and Parkinson’s can also often be treated with medication – but the effectiveness can wane, and DBS is reserved for the most severe cases. For difficult cases of narcolepsy, investigators have been willing to consider brain tissue transplants or immunotherapies in an effort to mitigate or interrupt neurological damage, and similar cost-benefit-risk analyses would have to take place for DBS.

Willie’s paper is also remarkable because it reflects how much is now known about how narcolepsy develops. Read more

Posted on July 16, 2020 by Quinn Eastman in Neuro Leave a comment

Autoimmune gene link for subtype of juvenile arthritis

GeneticistÂ Sampath Prahalad and the familiesÂ he works with wereÂ part of this recent PNAS paper, which probesÂ genetic risk factors for systemic juvenile idiopathic arthritis.

There are several subtypes of juvenile arthritis, and sJIA (systemic juvenile idiopathic arthritis) sounds especially painful because of its inflammatory symptoms: daily spiking fever and skin rashes in addition to joint pain.

The international team of investigators assembled what they report as the largest collectionÂ of sJIA patients (close to 1000) and identified HLA-DRB1*11 as a genetic risk factor for sJIA.

HLA-DRB1 alleles have also been linked to autoimmune diseases such as multiple sclerosis, type I diabetes and (adult) rheumatoid arthritis. The finding strengthens the case for trying existing medicationsÂ that target T cell activation in sJIA. Read more

Posted on December 7, 2015 by Quinn Eastman in Immunology Leave a comment

Decoding lupus using DNA clues

People with systemic lupus erythematosus can experience a variety of symptoms, such as fatigue, joint pain, skin rashes and kidney problems. Often the symptoms come and go in episodes called flares. In lupus, the immune system goes haywire and produces antibodies that are directed against the body itself.

A team of Emory scientists has been investigating some fundamental questions about lupus: where do the cells that produce the self-reactive antibodies come from? Are they all the same?

In the accompanying video, Kelli Williams, who helps study the disease and has lupus herself, describes what a flare feels like. In addition, Emory researchers IÃ±aki Sanz, MD and Chris Tipton, PhD explain their findings, which were published this summer inÂ Nature Immunology.

Judging by the number and breadth ofÂ abstractsÂ on lupus at the Department of Medicine Research DayÂ (where Tipton won 1st place for basic science poster),Â more intriguing findings are in the pipeline. Goofy Star Wars metaphors and more explanations of the scienceÂ here.

Posted on November 5, 2015 by Quinn Eastman in Immunology Leave a comment

Freezing stem cells disrupts their function

What applies to meat, vegetables and fish may also apply to cells for use in cell therapy: frozen often isn’t quite as good.

Ian Copland and colleagues from Emory’s Personalized Immunotherapy Center have a paper this week in Stem Cells Reports discussing how freezing and thawing stem cells messes them up. Specifically, it disrupts their actin cytoskeletons and impairs their ability to find their niches in the body. Culturing the cells for 48 hours after thawing does seem to correct the problem, though.

The findings have some straightforward implications for researchers planning to testÂ cell therapies inÂ clinical applications. The authors conclude:

Until such time as a cryopreservation and thawing procedure can yield a viable and fully functional MSC product immediately after thawing, our data support the idea of using live MSCs rather than post-thaw cryo MSCs for clinical evaluation of MSCs as an immunosuppressive agent.

Notably, the Emory Personalized Immunotherapy Center has built a process designed around offering never-frozen autologous (that is, the patient’s own)Â mesenchymal stem cells, as therapies for autoimmune disordersÂ such as Crohn’s disease.

Posted on June 6, 2014 by Quinn Eastman in Immunology Leave a comment