Abstract
INTRODUCTION: BK polyomavirus (BKPyV) in kidney transplant associated with adverse graft outcome. The aim of this study was to examine graft loss risk of BKPyV associated nephropathy (BKPyVAN) and BKPyV-DNAemia in relation with de novo donor-specific antibody (DSA) and rejection status. METHODS: Two hundred and forty patients from a multicentre cohort who had regular BKPyV and donor-DSA surveillance were retrospectively reviewed and stratified according to the presence of BKPyV-DNAemia and rejection. RESULTS: BKPyV-DNAemia did not associate with de novo DSA development (hazard ratio [HR] 1.15, 95% confidence interval [CI] 0.50-2.67, p = 0.74) but de novo DSA was more commonly observed in patients who developed rejection (BKV+/rejection- 4.3% (n = 2) vs. BKV+/rejection+ 57.1% (n = 4), p < 0.001). BKPyV-DNAemia (adjusted HR 4.02, 95% CI: 1.30-12.43, p = 0.016) and de novo DSA (adjusted HR 6.76, 95% CI: 2.51-18.24, p < 0.001) were independent factors associated with antibody-mediated rejection. Patients with BKPyV-DNAemia who were further complicated with rejection had approximately 6-fold risk of graft loss (adjusted HR 6.24, 95% CI: 2.04-19.09, p = 0.001), whereas patient with BKPyV-DNAemia alone did not experience significant increase graft loss risk (adjusted HR 1.76, 95% CI: 0.64-4.81, p = 0.27). CONCLUSIONS: Our study suggested that DSA monitoring would be warranted during immunosuppressant reduction for BKPyV-DNAemia and less aggressive reduction of immunosuppressant when DSA emerges might be a reasonable strategy to avoid overzealous reduction of immunosuppressant that could precipitate allograft rejection.