JAN 05, 2021 6:00 AM PST

Immune Imbalances Dictate COVID Symptom Severity

WRITTEN BY: Tara Fernandez

When it comes to COVID-19 symptoms, there seems to be a severity spectrum—some experience nothing but a headache, while others end up in critical care with a compromised respiratory system. Researchers have put this phenomenon under the microscope in search of the biological mechanisms at play that dictate patient outcomes. What they’ve found is that the immune system is a key influencer of COVID symptoms.

“As it is often the case for pathogenic infections, the host immune system is a key player in viral clearance and resolution of disease,” said immunology expert Lisa Ng from the Singapore Immunology Network (SIgN) and senior author in an article published in Nature Communications. 

“In this case, an imbalance between inflammation and protection leads to the progression to more severe disease.”

Ng and colleagues took a closer look at the immunological factors dictating COVID-19 progression by studying immune cells in the blood of 54 patients. This cohort presented with a wide range of clinical manifestations, from the milder symptoms all the way to fatal outcomes.

 

 

The scientists used high-dimensional flow cytometry (a lab-based technique for characterizing cells based on the expression of fluorescently-tagged proteins) to study a panel of over 50 types of immune cells. Two particular immune subtypes revealed themselves to be major players: lymphocytes and neutrophils.

The team found that T lymphocytes in COVID-19 patients had a sharp dip in the expression of CD8 and VD2, co-receptors that aid in T cell antigen interactions. At the same time, there was an uptick in the number of neutrophils that were relatively “immature” in their nature. Neutrophils make up around 55 to 70 percent of all white blood cells and form an essential component of the innate immune system. These cells mature in the bone marrow over the course of two weeks and it is unusual to find high proportions of immature neutrophils in circulation.

This is an important finding—immune cell ratios can be used as a prognostic marker to identify high-risk COVID-19 patients and provide them with early interventions. “We hope that our findings will allow for rapid triage possibilities in heavily burdened hospitals,” said Ng.

There are undoubtedly many more undiscovered nuances in the interplay between coronavirus infections and immune defenses, which Ng and her colleagues are currently exploring. “Hopefully, this can help guide therapies and inform vaccine or treatment design,” commented Ng.


Sources: Nature Communications, A*STAR Research.

About the Author
  • Tara Fernandez has a PhD in Cell Biology and has spent over a decade uncovering the molecular basis of diseases ranging from skin cancer to obesity and diabetes. She currently works on developing and marketing disruptive new technologies in the biotechnology industry. Her areas of interest include innovation in molecular diagnostics, cell therapies, and immunology. She actively participates in various science communication and public engagement initiatives to promote STEM in the community.
You May Also Like
OCT 05, 2020
Immunology
Can't Shed Those Extra Pounds? An Inflammatory Gene Could Be to Blame.
OCT 05, 2020
Can't Shed Those Extra Pounds? An Inflammatory Gene Could Be to Blame.
  Australian scientists have zeroed in on a gene linked to an increased obesity risk: a regulator of inflammation c ...
OCT 13, 2020
Immunology
Early Tips For Cell & Gene Therapy Regulatory Compliance
OCT 13, 2020
Early Tips For Cell & Gene Therapy Regulatory Compliance
Cell and gene therapies hold great promise for improved health outcomes. Now is the time to advance life-saving research ...
OCT 12, 2020
Drug Discovery & Development
Researchers Solve Key Problem for Cancer Immunotherapy
OCT 12, 2020
Researchers Solve Key Problem for Cancer Immunotherapy
Cancer immunotherapies are becoming increasingly promising as a standard-of-care treatment. However, despite their promi ...
OCT 21, 2020
Immunology
CNS's immune cells - Microglia are involved in the exacerbation of MS
OCT 21, 2020
CNS's immune cells - Microglia are involved in the exacerbation of MS
Multiple sclerosis (MS) is one of the most progressive autoimmune diseases that affect the central nervous system where ...
NOV 10, 2020
Immunology
Genetic Profiling Reveals How Ebola Puts Immune Cells in a Chokehold
NOV 10, 2020
Genetic Profiling Reveals How Ebola Puts Immune Cells in a Chokehold
In the middle of 2020, yet another deadly Ebola outbreak was reported in the Democratic Republic of the Congo - the 11th ...
DEC 29, 2020
Immunology
Cancer-Killing Viruses Enter in Stealth Mode, Penetrate Immune Barrier
DEC 29, 2020
Cancer-Killing Viruses Enter in Stealth Mode, Penetrate Immune Barrier
Viruses that when administered to patients preferentially attack and kill cancer cells, leaving normal tissues unscathed ...
Loading Comments...