title: Absence of Intragraft B Cells in Rejection Biopsies After Rituximab Induction Therapy: Consequences for Clinical Outcome.
abstract: BACKGROUND
  The pathophysiological role of intragraft B cells during renal allograft rejection is unclear.
  
  
  METHODS
  We studied B-cell infiltration during acute rejection in 53 patients who participated in a clinical trial in which adult renal transplant patients were randomized between a single intraoperative dose of rituximab (375 mg/m2) or placebo as induction therapy. Two independent pathologists scored all biopsies in a blinded fashion according to the Banff classification and scored for the presence of B cells and plasma cells using CD79a and CD138 as markers.
  
  
  RESULTS
  The majority of acute rejections were T cell-mediated. The proportion of acute rejections with an antibody-mediated component tended to be lower in rituximab-treated patients (4/23, 17.4%) than in placebo-treated patients (11/30, 36.7%;P= 0.14). Biopsies of rituximab-treated patients had significantly lower scores for B cells (0.00; range, 0.00-0.50 vs 1.70; range, 0.60-3.30;P< 0.0001) and plasma cells (0.10; range, 0.00-1.90 vs 0.40; range, 0.00-7.50;P= 0.006). During acute rejection, intragraft clusters of B cells were not observed after rituximab induction therapy. However, the depletion of intragraft B cells during acute rejection did not affect steroid resistance, proteinuria, graft function at 2 years follow-up, or patient and graft survival at a median follow-up of 4.1 years (range, 2.0-6.2 years).
  
  
  CONCLUSIONS
  These data do not support a harmful influence of intragraft B cells present during acute allograft rejection on the clinical course within the first few years after renal transplantation.
authors.affiliation: Renal Transplant Unit, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Martijn W F
authors.initials: MW
authors.lastname: van den Hoogen
authors.affiliation: Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Steenbergen
authors.affiliation: Department of Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Marije C
authors.initials: MC
authors.lastname: Baas
authors.forename: Sandrine
authors.initials: S
authors.lastname: Florquin
authors.affiliation: Department of Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Luuk B
authors.initials: LB
authors.lastname: Hilbrands