JUL 29, 2020 2:50 PM PDT

Immune Variation Explains Different COVID-19 Outcomes

WRITTEN BY: Kara Marker

Immune systems respond differently to coronavirus infection. People experience the disease causes by coronavirus, COVID-19, in different intensities, from moderate to severe. The two are connected, and the intricate details of one may help scientists predict the other.

From Yale University, scientists have uncovered specific indicators of how a positive COVID-19 case is likely to turn out: moderate or severe. One of the many mysteries of the COVID-19 pandemic has been how the virus affects people on such a wide spectrum of severity. With these indicators, researchers may provide a way to harness predictive power, thus guiding therapeutic regimens for high-risk patients.

The Yale study consisted of 113 patients with confirmed COVID-19, monitoring and measuring each participant’s unique and changing immune response to the infection for the entire duration of their stay in the hospital. When patients are in the beginning stages of COVID-19, many share the same immune “signature,” even though these patients may have very different outcomes as the disease runs its course.

In general, a moderate case of COVID-19 is characterized by an immune response and viral load that ultimately decreases over time as the infection is cleared by the body. But in severe disease, immune activity and viral load do not decrease. In some cases, it’s quite the opposite.

In the most severe cases of COVID-19, researchers have seen an excessive immune response to infection that leads to what is essentially “friendly fire.” This phenomenon of the body’s own inflammatory immune response wreaking havoc during infection has been called the “cytokine storm.” Cytokines are small cell signaling proteins with a wide array of functionalities, many with inflammatory associations.

With the onslaught of cytokine storms occurring in patients struggling with COVID-19, scientists have been asking: at what point do immune response levels blast past the threshold into dangerous, detrimental territory that has been characteristic of severe COVID-19 cases?

From their observations, Yale scientists identified severity risk indicators early on, when COVID-19 patients shared many characteristics, when a case that would ultimately end up in a long hospital stay looked just like one that would be recovered after not too long.

They found that high levels of a cytokine called alpha interferon were indicative of a risk for severe COVID-19. This cytokine is common in the immune response to viral pathogens, like the flu. Unlike other viral pathogens, coronavirus is not inhibited by alpha interferon, so the cytokine ends up doing more harm than good.

Another indicator is the activation of the inflammasome, a protein complex that mounts an inflammatory response in the presence of pathogenic infection.

There were also indicators of a COVID-19 case that was likely to be mild: high levels of growth factors, for tissue repair in the linings of blood vessels and lungs.

Sources: Yale University, Nature, International Anesthesiology Clinics

About the Author
  • I am a scientific journalist and enthusiast, especially in the realm of biomedicine. I am passionate about conveying the truth in scientific phenomena and subsequently improving health and public awareness. Sometimes scientific research needs a translator to effectively communicate the scientific jargon present in significant findings. I plan to be that translating communicator, and I hope to decrease the spread of misrepresented scientific phenomena! Check out my science blog: ScienceKara.com.
You May Also Like
AUG 06, 2020
Immunology
Resetting the Body's Danger Sensor
AUG 06, 2020
Resetting the Body's Danger Sensor
The human body has a sophisticated danger-sensing mechanism that alerts the immune system when something is not right. T ...
AUG 05, 2020
Immunology
Intercepting Cancer Cells Before They Can Dodge the Immune System
AUG 05, 2020
Intercepting Cancer Cells Before They Can Dodge the Immune System
The battle that naturally occurs between the body’s immune system and cancerous cells is one that scientists have ...
SEP 21, 2020
Cell & Molecular Biology
The Hormones We Have at Birth Are Linked to Disease Throughout Life
SEP 21, 2020
The Hormones We Have at Birth Are Linked to Disease Throughout Life
New work may help explain why some autoimmune or immune-related diseases are more common in women, who are more likely t ...
OCT 27, 2020
Immunology
The Genetics of Skin Inflammation, Seen With Unprecedented Clarity
OCT 27, 2020
The Genetics of Skin Inflammation, Seen With Unprecedented Clarity
A recent study published in Immunity details MIT scientists’ exploration of the underlying mechanisms of inflammat ...
NOV 12, 2020
Immunology
The Enzyme That Keeps Viruses In Stealth Mode
NOV 12, 2020
The Enzyme That Keeps Viruses In Stealth Mode
Some viral infections just don’t go away. The hepatitis C virus, for instance, can result in life-long chronic inf ...
NOV 10, 2020
Neuroscience
Nanoparticles Pass the Blood-Brain Barrier in Zebrafish
NOV 10, 2020
Nanoparticles Pass the Blood-Brain Barrier in Zebrafish
Video:  Explains the challenges of delivering medicine to the brain, and possibly tools to pass the blood-brain bar ...
Loading Comments...