Long-Term Elevated Inflammatory Protein Levels in Asymptomatic SARS-CoV-2 Infected Individuals

Area of Science:

• Immunology
• Infectious Diseases
• Virology

Background:

• SARS-CoV-2 infection presents a spectrum of clinical severity, from asymptomatic to critical illness.
• Understanding immune persistence in asymptomatic individuals is crucial for infection control.
• Long-term sequelae of SARS-CoV-2, even in mild cases, require further investigation.

Purpose of the Study:

• To investigate the persistence of antibody and T cell responses to SARS-CoV-2 in asymptomatic individuals 7-8 months post-infection.
• To identify potential long-term inflammatory effects associated with SARS-CoV-2 infection in this cohort.
• To correlate immune markers with viral neutralization capacity.

Main Methods:

• Analysis of antibody levels against SARS-CoV-2 Nucleocapsid (N) and Spike receptor-binding domain (S-RBD) proteins.
• Assessment of CD4+ T cell responses using CD137 and CD69 activation markers.
• Measurement of serum inflammation markers (S100A12, TGF-alpha, IL18, OSM) in antibody-positive individuals and seronegative controls.

Main Results:

• Antibodies to N protein declined 7-8 months post-infection, while S-RBD antibodies remained stable.
• S-RBD antibodies correlated with viral neutralization capacity and CD4+ T cell responses.
• Asymptomatic individuals showed elevated levels of macrophage-monocyte activation markers, indicating persistent inflammation.

Conclusions:

• SARS-CoV-2 infection can lead to long-term immune persistence and inflammation, even in asymptomatic cases.
• S-RBD antibody levels are a potential indicator of sustained cellular immunity.
• Post-infection clinical monitoring is recommended for asymptomatic SARS-CoV-2 individuals to detect persistent inflammatory effects.