Effects of complement activation on allograft injury

Area of Science:

• Immunology
• Transplantation Biology
• Complement System

Background:

• The complement system's role in transplant injury was historically limited to antibody-mediated damage.
• Recent research has expanded the understanding of complement's multifaceted involvement in post-transplant complications.

Purpose of the Study:

• To review current knowledge on complement system mechanisms in transplant injury.
• To highlight key findings published since 2013 regarding complement's role.

Main Methods:

• Literature review of studies published since 2013.
• Analysis of animal models and human studies on complement activation in transplantation.

Main Results:

• Complement activation is a key mediator of ischemia-reperfusion injury, with classical and lectin pathways playing significant roles.
• Complement influences alloreactive T-cell responses, inhibiting regulatory T cells and promoting rejection.
• Complement contributes to endothelial cell activation, inflammation, and chronic allograft fibrosis.

Conclusions:

• The complement cascade impacts transplant injury through multiple pathways beyond antibody-initiated damage.
• Complement activation exacerbates ischemia-reperfusion injury, alloantibody formation, T-cell responses, and chronic allograft failure.
• Targeting the complement system presents a potential therapeutic avenue for enhancing transplant outcomes.