Protocol Biopsies in Patients with Subclinical De Novo DSA After Kidney Transplantation
Résumé
BACKGROUND:
De novo donor-specific antibodies (DSA) are associated with antibody-mediated rejection (AMR) and allograft loss. Whether monitoring of de novo DSA (dnDSA) paired with systematic kidney biopsy should become routine remains to be established.
METHODS:
A retrospective multicentric study (9 French kidney transplant units of the Spiesser Group) included patients without graft dysfunction biopsied because of the presence of de novo DSA (One Lambda, MFI > 1000).
RESULTS:
123 patients (85M/38F; mean age: 49.5 ± 13.1 years old) were biopsied after the detection of a dn DSA, 65.3 months (median) after kidney transplantation. Graft function was stable within 3 months before biopsy (estimated glomerular filtration rate (eGFR): 55.3 ± 18.9 ml/min/1.73m²). Fifty-one subclinical AMR (sAMR) (41.4%) were diagnosed, of which 32 (26%) active and 19 (15.5%) chronic active sAMR. Seventy-two biopsies revealed no AMR (58.5%). Predictive factors associated with the diagnosis of active sAMR were MFI of immunodominant DSA > 4000, MFI of the sum of DSA > 6300, age of the recipient < 45 y, and the absence of steroids at biopsy. The presence of proteinuria > 200 mg/g was predictive of chronic active sAMR. The decrease of eGFR at 5 years post biopsy was significantly higher in patients with acute sAMR (-25.2 ± 28.3 mL/min/1.73m²) and graft survival significantly lower.
CONCLUSION:
Performing a kidney graft biopsy for the occurrence of dnDSA without renal dysfunction leads to the diagnosis of a sAMR in over 40% of cases. Neverthess, we did not observe any effect of standard treatment in acute sAMR.