T-Helper Cell Subset Response Is a Determining Factor in COVID-19 Progression

Area of Science:

• Immunology
• Virology
• Infectious Diseases

Background:

• The immune response is critical in determining the outcome of viral infections.
• T-helper (Th) cell polarization plays a significant role in managing viral infections.

Purpose of the Study:

• To investigate T-helper cell polarization in acute COVID-19.
• To explore the association between Th cell profiles and COVID-19 patient outcomes.

Main Methods:

• Prospective observational study involving 55 COVID-19 patients.
• Analysis of T-helper cell percentages and phenotypes using flow cytometry.
• Quantification of serum cytokine levels via Luminex assay.

Main Results:

• COVID-19 patients exhibited reduced Th1 and Th17 cells, with increased activated Th2 cells compared to controls.
• Higher percentages of senescent Th2 cells were observed in non-survivors.
• Senescent Th2 cells (OR: 13.88) and lower lymphocyte counts (OR: 0.15) were independent risk factors for mortality.
• Elevated pro-inflammatory cytokines (IL-2, IL-6, IL-15, IP-10) and IL-10, IL-13 were found in patients.
• Increased IL-15 levels were significantly associated with fatal outcomes.

Conclusions:

• A pronounced Th2 response and elevated IL-15 levels are linked to a fatal outcome in COVID-19.
• Senescent Th2 cells represent a significant independent risk factor for COVID-19 mortality.