HLA antibodies are associated with deterioration of kidney allograft function irrespective of donor specificity

Background Donor-specific antibodies are associated with high immunological risk and poor allograft outcome. Risk and clinical relevance of non-donor-specific HLA antibodies is less clear. Methods A retrospective single-center study was conducted in all patients receiving a first kidney transplant at the University hospital of Zurich between 01/2006 and 02/2015. Patients were stratified into 3 groups having either no HLA antibodies at all (NoAB), HLA antibodies with donor specificity (DSA) and HLA antibodies without donor specificity (NonDSA). Allograft outcome was assessed using the slope of the estimated glomerular filtration rate (eGFR slope) starting at 12 months after transplantation. Results During a median follow-up of 1808 days HLA antibodies were detected in 106 of 238 eligible patients (44%). Out of these, 73 patients (69%) had DSA and 33 patients (31%) had NonDSA only. Medium-term allograft function, as determined by eGFR slope over three years, improved in patients with NoAB (months 12–48: +0.7 ml/min/1.73 m2) but deteriorated significantly in patients with both DSA (months 12–48: −1.5 ml/min per1.73 m2/year, p = 0.015) and NonDSA (months 12–48: −1.8 ml/min per1.73 m2/year, p = 0.03) as compared to the group with NoAB. Conclusion Both, donor-specific and non-donor-specific HLA antibodies are associated with medium-term kidney allograft dysfunction as compared to patients with no HLA antibodies.