title: Renal allograft biopsies in the era of C4d staining: the need for change in the Banff classification system.
abstract: C4d immunostaining in the peritubular capillaries (PTC) is a marker of antibody-mediated rejection (AMR). We evaluated the histopathologic diagnoses of 388 renal transplant biopsies since the implementation of routine C4d immunostaining at our center. Of these, 155 (40%) biopsies had evidence of acute cellular rejection (ACR), out of which 119 (77%) had pure ACR, 31 (20%) had ACR with concomitant features of AMR, and five (3%) had ACR with focal C4d staining. Sixty-four (16%) biopsies exhibited features of AMR [33 (52%) pure AMR, and 31(48%) concomitant AMR and ACR]. One hundred and fifty-five (40%) biopsies had features of interstitial fibrosis and tubular atrophy (IFTA). Of these, 20 (13%) had concomitant AMR [13 (8.5%) had pure AMR and seven (4.5%) had concomitant ACR and AMR]. Creatinine at the time of biopsy was higher in patients with mixed ACR and AMR and the clinical behavior of mixed lesions is more aggressive over time. Despite having a lower serum creatinine at the time of biopsy, patients with IFTA experienced gradual decline in graft function over time. The pathologic findings in renal allograft biopsies are often mixed and mixed lesions appear to have more aggressive clinical behavior. These findings suggest the need for change in the Banff classification system to better capture the complexity of renal allograft pathologies.
authors: Division of Nephrology, Saint Louis University, Saint Louis, MO, USA. zalaly@slu.edu
authors: Ziyad
authors: Z
authors: Al-Aly
authors: Venkata
authors: V
authors: Reddivari
authors: Abdul
authors: A
authors: Moiz
authors: Geetha
authors: G
authors: Balasubramanian
authors: Cherise M
authors: CM
authors: Cortese
authors: Luis
authors: L
authors: Salinas-Madrigal
authors: Bahar
authors: B
authors: Bastani
mesh_terms: D000328:Adult; D001284:Atrophy; D001706:Biopsy; D002196:Capillaries / Q000473:pathology; D015935:Complement C4b / Q000032:analysis*; D005260:Female; D006084:Graft Rejection / Q000145:classification / Q000473:pathology*; D006801:Humans; D016030:Kidney Transplantation / Q000473:pathology*; D007684:Kidney Tubules / Q000473:pathology; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D010446:Peptide Fragments / Q000032:analysis*; D012079:Renal Circulation
chemical_list: D010446:Peptide Fragments; D015935:Complement C4b; C032261:complement C4d