Complement Alternative Pathway Deficiency in Recipients Protects Kidney Allograft From Ischemia/Reperfusion Injury...

Area of Science:

• Immunology
• Transplantation Biology
• Nephrology

Background:

• Kidney transplant long-term survival remains suboptimal despite advancements in immunosuppression.
• Early intragraft inflammation, particularly complement activation via the alternative pathway (AP), drives alloimmune responses and impacts graft function.
• Ischemia/reperfusion injury (IRI) and adaptive immunity in transplantation involve complement activation.

Purpose of the Study:

• To investigate the potential of selectively blocking the AP of complement as a strategy to improve kidney transplant outcomes.
• To determine if inhibiting AP can mitigate IRI and T cell-mediated rejection.
• To explore the role of AP in direct and indirect alloantigen presentation pathways.

Main Methods:

• Transplantation of Balb/c kidneys into factor B (fB)-deficient C57 mice.
• In vitro studies assessing T cell and dendritic cell alloreactive/allostimulatory functions in fB-deficient cells.
• Administration of anti-fB antibody to C57 wild-type recipients post-kidney transplantation.

Main Results:

• Kidneys transplanted into fB-deficient mice showed reduced IRI and diminished T cell-mediated rejection.
• fB deficiency in T cells and dendritic cells impaired their alloreactive and allostimulatory functions, respectively.
• Early inhibition of AP with anti-fB antibody prolonged kidney graft survival by mitigating IRI and adaptive immune responses.

Conclusions:

• Selective blockade of the alternative complement pathway is a promising strategy for improving kidney transplant survival.
• Inhibition of AP during critical early post-transplant phases is crucial for graft protection.
• AP inhibitors may represent a novel therapeutic approach for clinical kidney transplantation.