Hyper-inflammation and complement in COVID-19

Area of Science:

• Immunology
• Virology
• Pathobiology

Background:

• COVID-19 presents a wide spectrum of severity, with hyperinflammation and complement system over-activation playing key roles in severe cases.
• The SARS-CoV-2 virus can directly activate the complement system through multiple pathways, contributing to disease severity.
• Intracellular complement activation (the complesome) within infected cells is also implicated in COVID-19 pathogenesis.

Purpose of the Study:

• To explore the role of complement system over-activation in severe COVID-19.
• To evaluate the potential therapeutic benefits of complement inhibition in COVID-19 patients.
• To understand the mechanisms by which SARS-CoV-2 interacts with the complement system.

Main Methods:

• Review of existing literature on COVID-19, complement biology, and therapeutic strategies.
• Analysis of data from early-phase clinical trials (Phase I and II) investigating complement inhibitors.
• Hypothesizing optimal targets and timing for complement inhibition based on pathway knowledge.

Main Results:

• Complement over-activation is strongly associated with COVID-19 severity, microangiopathy, and hypercoagulability.
• Early clinical trials show promising but conflicting results for complement inhibition therapies.
• Upstream complement cascade inhibition is proposed as a potentially more effective strategy to block hyperinflammation.

Conclusions:

• Complement system dysregulation is central to severe COVID-19.
• Targeting the complement system therapeutically holds potential for treating severe COVID-19.
• Further randomized controlled trials (Phase III) are necessary to confirm efficacy and optimal strategies for complement inhibition.