Baseline Characteristics
ABMR, TOf, toxicity, tubulitis, arteritis, TCMR, acute tubular injury, inflammation, proteinuria, interstitial nephritis, nephropathy, peritubular capillaritis, tubular atrophy
GLOMERULITIS, ARTERITIS, INFLAMMATION, INTERSTITIAL NEPHRITIS, INTERSTITIAL FIBROSIS, NEPHROPATHY, CAPILLARITIS, ANTIBODY-MEDIATED REJECTION
From November 2020 to December 2022, 106 kidney transplant recipients with a total of 108 graft biopsies were enrolled. dd-cfDNA was quantified at day of indication biopsy (TOf the 108 allograft biopsies, 36 (33%) were classified as different types of rejection, whereof 7 biopsies were graded as ABMR, 6 as TCMR, and 23 as borderline changes (Heat map of histopathological lesion scores according to the BANFF classification and the polyomavirus-associated interstitial nephritis score as well as donor-derived cell-free DNA levels and the presence of donor-specific and non-HLA antibodies for 108 kidney allograft biopsies. The 108 allograft biopsies are grouped according to histopathological diagnosis. Color-coding indicates BANFF lesion scores and dd-cfDNA levels. The presence of donor-specific antibodies with a mean fluorescence intensity of >500 and >1,000, as well as the presence of any non-HLA antibodies is indicated in purple. ABMR, antibody-mediated rejection; ah, hyaline arteriolar thickening; ATI, acute tubular injury; BKVAN, BK virus-associated nephropathy; cg, glomerular basement membrane double contours; ci, interstitial fibrosis; CNI, calcineurin-inhibitor toxicity; ct, tubular atrophy; cv, vascular fibrous intimal thickening; dd-cfDNA, donor-derived cell-free DNA; DSA, donor-specific antibodies; g, glomerulitis; i, interstitial inflammation; IFTA, interstitial fibrosis and tubular atrophy; mm, mesangial matrix thickening; non-HLA AB, non-HLA antibodies (angiotensin II type 1 receptor/endothelin receptor subtype A/major histocompatibility complex class I-related chain A); ptc, peritubular capillaritis; PVI, polyomavirus-associated interstitial nephritis score; t, tubulitis; v, intimal arteritis; TCMR, T cell-mediated rejection; i-IFTA, inflammation in the area of IFTA. (*) Two biopsies showed mixed rejection with concomitant borderline lesions and were categorized as ABMR due to low numbers of mixed rejections. (**) Based on clinical judgement, this biopsy was categorized as borderline changes, despite the presence of glomerulitis, peritubular capillaritis, C4d deposition, and low-level DSA (MFI 505). Of note, the biopsy was conducted 14 days after a living kidney donation, DSA were not detected subsequently and eGFR as well as dd-cfDNA improved upon sole corticosteroid treatment.Patient characteristics stratified for active rejection vs. no rejection are shown in Clinical characteristics in kidney transplant recipients with indication biopsy stratified for status of rejection.The data includes two patients with re-biopsies after completed follow-up. dd-cfDNA, donor-derived cell-free DNA; DSA, donor-specific anti-HLA antibodies; non-HLA AB, non-HLA antibodies including antibodies targeting the major histocompatibility complex class I-related chain A (MICA), angiotensin II type 1 receptor (AT1R) and endothelin receptor subtype A (ETA); ***Not possible to determine DSA in two patients due to missing data.Not possible to determine DSA in three patients due to missing data.Data on proteinuria were only available in 29 patients with active rejection and 56 patients without active rejection.The bold values reflect significance.