Genotypic diversity of complement component C4 does not predict kidney transplant outcome

Area of Science:

• Immunogenetics
• Transplantation Immunology
• Molecular Biology

Background:

• The classical complement pathway plays a role in transplant rejection.
• Complement component C4 (C4) gene copy number varies significantly among individuals.
• C4 genetic diversity may influence the classical complement pathway's intrinsic strength.

Purpose of the Study:

• To investigate the association between C4 gene copy number and kidney transplant outcomes.
• To determine if C4 genetic diversity explains variations in allograft survival and rejection rates.

Main Methods:

• Retrospective analysis of 1969 deceased-donor kidney transplants.
• Quantitative real-time PCR to determine recipient and donor C4 gene copy number (total C4, C4A, C4B, C4L, C4S).
• Analysis of graft survival, dysfunction, rejection, infection, malignancy, and death across different C4 genotype groups.

Main Results:

• Recipient C4 gene copy number (low, intermediate, high) did not correlate with 10-year allograft survival.
• No significant differences were observed in graft dysfunction, rejection treatment, immunological graft loss, infection, malignancy, or death among genotypic groups.
• Separate and combined analyses of C4 isotypes and gene length variants, including in high-risk recipients, showed no considerable impact on transplant outcomes.

Conclusions:

• C4 gene copy number is not associated with kidney transplant outcomes.
• Variation in classical complement activation strength due to C4 gene copy number does not appear to influence susceptibility to transplant rejection.