title: Renal Transplant Recipients Treated with Calcineurin-Inhibitors Lack Circulating Immature Transitional CD19+CD24hiCD38hi Regulatory B-Lymphocytes.
abstract: BACKGROUND
  CD19+CD24hiCD38hi transitional immature B-lymphocytes have been demonstrated to play an important role in regulating the alloimmune response in transplant recipients. Here, we analyzed the effect of calcineurin inhibition on these peripherally circulating regulatory B-cells (Breg) in renal transplant recipients receiving cyclosporine A (CsA) or tacrolimus.
  
  
  METHODS
  PBMCs from healthy subjects (HS) (n = 16) and renal transplant recipients (n = 46) were isolated. Flow cytometry was performed for CD19, CD24, CD38 and IL-10 either after isolation or after 72 hours of co-culture in presence of PMA/Ionomycin and TLR9-ligand in presence or absence of increasing concentrations of tacrolimus or CsA.
  
  
  RESULTS
  The amount of CD19+ B-cells among lymphocytes was ∼9.1% in HS, ∼3.6% in CsA (n = 11, p<0.05) and ∼6.4% in TAC (n = 35, p<0.05) treated patients. Among B-cells, a distinct subset of Breg was found to be 4.7% in HS, 1.4% in tacrolimus treated patients and almost blunted in patients receiving CsA. Similarily, ∼4% of B-cells in HS and even fewer in CsA or tacrolimus treated patients produced IL-10 (0.5% and 1.5%, p<0.05) and this was confirmed both in non-transplanted CsA-treated healthy subjects and in in vitro co-culture experiments. Among 29 patients with <1% of Breg, 9 cases (31%) displayed an allograft rejection in contrast to only one case of rejection (6%) among 17 patients with >1%.
  
  
  CONCLUSIONS
  Calcineurin inhibitors reduce number and IL-10 production of Bregs in the peripheral circulation of both renal transplant recipients and non-transplanted healthy subjects. CNI induced Breg reduction is not restricted to a solid organ transplant setting and is not mediated by co-medication with steroids or MPA. A low proportion of Breg cells is associated with an elevated frequency of allograft rejection events.
authors.affiliation: Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: Tebbe
authors.affiliation: Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Wilde
authors.affiliation: Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Zeng
authors.initials: Z
authors.lastname: Ye
authors.affiliation: Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Junyu
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.|Department of Pediatrics II, Pediatric Nephrology, Gastroenterology, Endocrinology and Transplant Medicine, Children's Hospital Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Xinning
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Fu
authors.initials: F
authors.lastname: Jian
authors.affiliation: Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.|Department of Infectious Diseases, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Dolff
authors.affiliation: Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Schedlowski
authors.affiliation: Department of Pediatrics II, Pediatric Nephrology, Gastroenterology, Endocrinology and Transplant Medicine, Children's Hospital Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Peter F
authors.initials: PF
authors.lastname: Hoyer
authors.affiliation: Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kribben
authors.affiliation: Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.|Department of Infectious Diseases, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Witzke
authors.affiliation: Department of Pediatrics II, Pediatric Nephrology, Gastroenterology, Endocrinology and Transplant Medicine, Children's Hospital Essen, University Duisburg-Essen, Essen, Germany.|Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Hoerning
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000276:immunology*; D060151:B-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism; D065095:Calcineurin Inhibitors / Q000627:therapeutic use*; D016022:Case-Control Studies; D018920:Coculture Techniques; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D016753:Interleukin-10 / Q000096:biosynthesis; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D015703:Antigens, CD; D065095:Calcineurin Inhibitors; D016753:Interleukin-10