The relevance of complement C4d staining in renal allograft biopsies

Abstract

In renal transplant, the allograft is affected by many triggering agents such as innate and adaptive immune mechanisms, either mediated by macrophages and lymphocytes, or by soluble components antibodies and the complement system, which can ultimately lead to graft rejection. Antibody-mediated rejection (AMR) is a predominant cause of allograft failure. Donor-specific antibodies, mostly reactive to human leukocyte antigen antigens, are now considered by pathologists and clinicians as a significant cause of early and late graft dysfunction and failure. Complement 4d (C4d) is a fragment of the classical complement pathway (that is a part of component C4), which is activated by antigen-antibody complexes. The diagnosis of AMR improves by detection of the complement fragment C4d in renal biopsy, and it has included for diagnosis of AMR in the year 2003. There is more development about C4d after inclusion in the diagnostic criteria of AMR. This review aims to evaluate pathogenesis and current relevance of C4d in AMR.

Keywords

• antibody-mediated rejection
• complement 4d
• donor-specific antibodies
• positive