Renal transplant outcomes and de novo donor-specific anti-human leukocyte antigen antibodies: a systematic review

Background Pre-transplant donor-specific anti-human leukocyte antigen antibodies (DSAs) are known risk factors for acute rejection and reduced graft survival after kidney transplantation. DSAs may also develop de novo DSAs (dnDSAs) after transplantation but the clinical implications of these antibodies remain uncertain. Methods We undertook a systematic review of observational studies that examined the association between dnDSAs and graft and patient outcomes (through August 2017) with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system of reporting used to assess the quality of evidence available. Results Thirty-six studies involving 10 535 transplant recipients were eligible. There was moderate quality evidence that transplant recipients who developed dnDSAs had increased risks of acute antibody-mediated rejection (AMR) [relative risk (RR) 9.66; 95% confidence interval (CI) 6.79-13.73, 16 studies, n = 4174]. For all other outcomes, the evidence was low to very low due to moderate-high heterogeneity and low study quality (acute cellular rejection, RR 2.92; 95% CI 2.16-3.94, 22 studies, n = 4991, low-quality evidence; chronic AMR and transplant glomerulopathy RR 6.78; 95% CI 4.31-10.66, 3 studies, n = 1617, very low-quality evidence; and graft loss RR 4.95; 95% CI 3.81-6.43, 19 studies, n = 5473, low-quality evidence). Meta-regression indicated that deceased kidney donation (R2 = 1.00, P