Virus Induced Pathogenic Antibodies - Lessons from Long COVID and Dengue

Medical News: Understanding How the Immune System Can Turn Against the Body
The immune system plays a critical role in defending the body against viruses and infections. However, in some cases, the body's own defense mechanisms can become harmful. Scientists have been closely studying how virus-induced antibodies, which are normally beneficial, can sometimes worsen diseases instead of fighting them off. New research highlights how certain antibodies contribute to severe illness in both long COVID and dengue hemorrhagic fever (DHF), two conditions that show alarming similarities in how the immune system reacts.


Virus Induced Pathogenic Antibodies - Lessons from Long COVID and Dengue

This Medical News report examines the latest scientific findings on how these antibodies influence disease progression. Researchers from Tzu-Chi University in Taiwan conducted an in-depth analysis, comparing the roles of pathogenic antibodies in long COVID and DHF. Their findings could help shape new treatment strategies and improve vaccine development to prevent harmful immune reactions.
 
How Pathogenic Antibodies Affect Long COVID and DHF
Antibodies are proteins produced by the immune system to neutralize harmful invaders like viruses. While they are usually protective, some can have the opposite effect, leading to excessive inflammation and tissue damage. The study found that in long COVID and DHF, specific types of antibodies play a central role in causing harm instead of offering protection.
 
In Long COVID:
-The immune system continues to produce antibodies long after the virus is gone.
 
-Some of these antibodies mistakenly target healthy tissues, leading to chronic inflammation and organ damage.
 
-Patients suffer from persistent symptoms, including fatigue, brain fog, and heart problems.
 
-Autoantibodies - antibodies that attack the body's own cells - have been found at high levels in long COVID patients, affecting key receptors in the body.
 
In Dengue Hemorrhagic Fever:
-Instead of protecting against the virus, pre-existing antibodies can worsen the infection through a process called Antibody-Dependent Enhancement (ADE).
 
-ADE allows the dengue virus to infect immune cells more effectively, leading to severe inflammation and increased risk of internal bleeding.
 
-Patients develop plasma leakage, a serious condition where fluids escape from blood vessels, leading to shock and organ failure.
 
The Role of Antibody Dependent Enhancement in Worsening Disease
Antibody-Dependent Enhancement (ADE) is a major concern in viral infections like dengue and COVID-19. The study explains how ADE occurs when antibodies bind to a virus but fail to neutralize it. Instead, they help the virus enter immune cells more easily, leading to increased viral replication and severe disease.
 
For dengue, ADE is one of the main reasons why a second infection can be much worse than the first. The immune system, having been exposed to the virus before, produces antibodies that do not fully block the virus. Instead, these antibodies assist the virus in infecting more cells, triggering a severe immune response that damages blood vessels.
 
With COVID-19, researchers believe ADE could also play a role, particularly in some vaccinated individuals who experience breakthrough infections. However, the exact extent of its impact on long COVID is still under investigation.
 
Autoantibodies and Immune Dysregulation in Long COVID
One of the key findings of the study is the role of autoantibodies in long COVID. These are antibodies that mistakenly target the body’s own tissues and organs, leading to long-term health issues. Researchers found high levels of autoantibodies in long COVID patients, particularly those affecting receptors in the nervous system, blood vessels, and immune system.
 
Some of the key autoantibodies identified include:
-ACE2-targeting autoantibodies: Affecting the receptor that the SARS-CoV-2 virus uses to enter cells, possibly disrupting blood pressure and circulation.
 
-Muscarinic receptor autoantibodies: Linked to neurological symptoms such as dizziness and memory problems.
 
-Beta-adrenergic receptor autoantibodies: Potentially contributing to heart palpitations and abnormal heart rates seen in many long COVID cases.
 
The presence of these autoantibodies suggests that long COVID is not just a lingering viral infection but a condition driven by immune system dysfunction, making it similar to autoimmune diseases.
 
Implications for Treatment and Vaccine Development
The discovery of these pathogenic antibodies raises concerns about how vaccines and treatments should be designed to minimize the risk of ADE and autoantibody production.
 
For Long COVID:
-Immunomodulatory therapies, such as intravenous immunoglobulin (IVIg) and plasmapheresis, are being explored as potential treatments.
 
-Identifying biomarkers for autoantibody activity could help diagnose long COVID earlier and predict which patients are at higher risk of severe complications.
 
-Future vaccines should aim to reduce the risk of triggering autoantibody production while still providing strong immunity against the virus.
 
For Dengue Hemorrhagic Fever:
-Researchers emphasize the importance of vaccine designs that prevent ADE, as seen with past dengue vaccine trials that led to increased severe cases in some recipients.
 
-Early interventions targeting inflammation and immune responses may help prevent severe cases of DHF in at-risk individuals.
 
Conclusion
The study sheds new light on how virus-induced antibodies can sometimes do more harm than good. In both long COVID and DHF, immune dysregulation driven by pathogenic antibodies plays a significant role in disease severity. Long COVID is marked by the persistence of autoantibodies that attack the body's own tissues, leading to long-term health problems, while dengue hemorrhagic fever is exacerbated by antibody-dependent enhancement, which increases viral replication and worsens symptoms.
 
Understanding these immune processes is crucial for developing better treatments and vaccines that minimize the risks associated with harmful antibody responses. Future research should focus on identifying reliable biomarkers for predicting severe outcomes, exploring new therapeutic options that reduce pathogenic antibody activity, and refining vaccine strategies to avoid triggering harmful immune reactions. These insights are vital for improving global health and mitigating the long-term impacts of viral infections.
 
The study findings were published in the peer-reviewed International Journal of Molecular Sciences.
https://www.mdpi.com/1422-0067/26/5/1898
 
For the latest on Antibodies and Autoantibodies, keep on logging to Thailand Medical News.
 
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