Evidence for Antibody-Mediated Injury as a Major Determinant of Late Kidney Allograft Failure

TLDR

Late graft failure is thought to result from immunologic and non‑immunologic insults that progressively damage kidney function. The study aimed to determine whether C4d staining and circulating donor‑specific antibodies predict subsequent graft failure in patients with new onset late kidney dysfunction. Researchers analyzed 173 kidney transplant recipients, categorizing them by C4d and DSA status, and used blinded pathology and central DSA testing to compare outcomes. Patients with both C4d positivity and donor‑specific antibodies had the highest risk of graft failure, and C4d+ staining alone was associated with a significantly increased risk of late graft failure, indicating that antibody‑mediated injury is a major determinant of late kidney allograft failure.

Abstract

Late graft failure (LGF) is believed to be the consequence of immunologic and nonimmunologic insults leading to progressive deterioration in kidney function. We studied recipients with new onset late kidney graft dysfunction (n=173) to determine the importance of C4d staining and circulating donor-specific antibody (DSA) in subsequent LGF.One hundred seventy-three subjects transplanted before October 1, 2005 (mean time after transplant 7.3+/-6.0 years) had a baseline serum creatinine level of 1.4+/-0.3 mg/dL before January 1, 2006 and underwent biopsy for new onset graft dysfunction after that date (mean creatinine at biopsy 2.7+/-1.6 mg/dL). Statistical analysis was based on central DSA and blinded pathology determinations.Subjects were divided into four groups based on C4d and DSA: no C4d, no DSA (group A; n=74); only DSA (group B; n=31); only C4d (group C; n=28); and both C4d and DSA (group D; n=40). Among DSA+ recipients (groups B and D), group D had broader reactivity and a stronger DSA response. After 2 years, groups C and D (C4d+) were at significantly greater risk for LGF than groups A and B. Adjusting for inflammation (Banff i, t, g, and ptc scores) did not change the outcome. Local diagnosis of calcineurin inhibitor nephrotoxicity was spread across all four subgroups and did not impact risk of LGF.Evidence of antibody-mediated injury (DSA or C4d) is common (57%) in patients with new onset late kidney allograft dysfunction. The risk of subsequent graft failure is significantly worse in the presence of C4d+ staining.