The role of anti-HLA donor specific antibodies (DSA) in increasing the risk of graft rejection is known. Nevertheless, not all patients with DSA develop rejection and DSA levels before transplantation are not good predictors. Our group has previously found that the increase on DSA levels after transplantation is associated with higher frequency of antibody-mediated rejection (ABMR), while the decrease is protective.Regulatory T and B cells (Treg;Breg) are reported to play a role in the control of inflammatory response to allografts.The aim of this study was to evaluate the frequency of regulatory cells and its relation with DSA, ABMR and transplantation outcome. We analyzed DSA levels over 2 years(by Single Antigen) and the circulating Tregs, Bregs and memory cells (by flow cytometry)at 18 and 24 months post-transplant, in 60 patients: 31 (51,7%) with PRA=0, 18 (30%) PRA>0 and no DSA, and 11 (18,3%) with pre-transplant DSA. T-cell mediated rejection (TCMR) occurred in 14 (23,3%) patients in a median time of 396 days. ABMR occurred in 7 (11,7%) in a median of 19 days. Patients who presented rejection, showed higher percentage of TCD4 memory (39,8 vs 31,2; p=0,0279), Breg (6,92 vs 4,76; p=0,0127) and Treg (4,41 vs 3,68; p=0,0433) compared to patients without rejection. Also,patients with ABMR, had higher percentages of Breg and lower B memory (12,90 vs 6,21; p=0,0341 and 8,12 vs 22,45; p=0,0098) compared to those with TCMR. Patients with post-transplant DSA showed higher Breg (6,26 vs 4,06; p= 0,0181) and lower B memory (22,85 vs 29,80; p=0,0456) compared to patients without DSA. Those who kept their grafts after decreasing DSA levels, following ABMR treatment, had higher Breg/Bmemory ratio (1,75 vs 0,22; p=0,0036) and higherTreg (3,76 vs 1,21; p=0,0010) compared to who decreased DSA levels spontaneously, without rejection.Sensitized patients without DSA failed to show any changes on cell subsets.We suggest that acute rejection (especially ABMR) as well as ABMR treatment led to the increase on circulating regulatory cells, which can help controlling rejection, and avoiding graft lost. Our data also point to a significant relationship between DSA presence, even in the absence of ABMR, and upregulation of a B-cell regulatory profile.

CITATION INFORMATION: Maciel G., Fernandes M., Barbosa E., Rodrigues H., Panajotopolus N., Agena F., David-Neto E., Coelho V., Castro M. Increase on Regulatory Cells in Kidney Transplanted Patients Presenting Donor-Specific Antibodies Am J Transplant. 2017;17 (suppl 3).

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