T Regulatory Cell Subsets Do Not Restore for One Year After Acute COVID-19

Area of Science:

• Immunology
• Virology
• Cell Biology

Background:

• COVID-19 (SARS-CoV-2) induces a complex immune response.
• T regulatory cells (Tregs) are vital for immune homeostasis and controlling inflammation.
• Understanding Treg dynamics during COVID-19 is crucial for managing immune responses.

Purpose of the Study:

• To investigate the role and function of T regulatory cells during acute COVID-19 and recovery.
• To analyze Treg subpopulations and their functional markers in COVID-19 patients.
• To correlate Treg changes with inflammatory markers and disease severity.

Main Methods:

• Analysis of peripheral blood Treg subpopulations ('naïve', CM, EM, TEMRA) using flow cytometry.
• Assessment of Treg functional state via CD39 and CD73 expression.
• Quantification of cytokine profiles using multiplex analysis.

Main Results:

• Tregs significantly decreased during acute COVID-19, correlating with higher inflammation and severity.
• Specific Treg subsets ('naïve', CM) showed reduced absolute numbers, while EM Tregs increased.
• Treg counts partially recovered in convalescence, but long-term deficits remained one year post-infection.
• CD39 expression on Tregs was re-established, but CD73 expression remained unchanged.

Conclusions:

• COVID-19 significantly impacts Treg populations and function, contributing to immune dysregulation.
• Persistent Treg alterations post-recovery suggest long-term immunological consequences.
• Insights into Treg dynamics and purinergic signaling aid understanding of COVID-19 pathogenesis and recovery.