title: Impairment of circulating myeloid dendritic cells in immunosuppressed renal/pancreas transplant recipients.
abstract: BACKGROUND
  Immunosuppressive drugs used after organ transplantation are known to impair lymphocyte function, resulting in an increased incidence of viral associated malignancies. In vitro data indicate that immunosuppressive drugs also target dendritic cells (DCs). Our study aimed to investigate the phenotype and function of circulating myeloid DCs (mDCs) from renal/pancreas transplant recipients receiving immunosuppressive drugs. In addition, we analyzed the potential of patient monocytes to differentiate into mature DCs (MoDCs) in vitro.
  
  
  METHODS
  Phenotype of mDCs was analyzed by fluorescence-activated cell sorter (FACS) analysis. The ability of mDCs to undergo activation was determined using cytokine bead array and FACS analysis. Allostimulatory capacity was determined by mixed leukocyte reaction. MoDCs were generated using a defined cytokine cocktail and analyzed for maturity of phenotype and function. The ability of patient-MoDCs to expand antigen-specific T cells was analyzed by tetramer staining and interferon (IFN)-gamma ELISPOT assay.
  
  
  RESULTS
  We observed a reduced expression of CD54 (P=0.001), CD86 (P=0.032), HLA-DR (P=0.013), and CD38 (P=0.006) on patient mDCs. Upon stimulation, the expression of HLA-ABC, HLA-DR and CD86 was upregulated on patient mDCs to the same level as on control mDCs. MoDCs were equivalent to control-MoDCs regarding phenotype and function. Co-culture of peptide-pulsed patient-MoDCs with T cells resulted in significant expansion of autologous Epstein-Barr virus-specific, IFN-gamma secreting T cells.
  
  
  CONCLUSIONS
  Our data support the notion that immunosuppressive drugs target DCs and induce a maturation defect in circulating mDCs. However, ex vivo stimulated mDCs as well as MoDCs do not show a significant impairment, suggesting that MoDCs from immunosuppressed patients can be used for immunotherapeutic strategies.
authors.affiliation: Med. Klinik m. S. Hämatologie/Onkologie, Charité-Universitätsmedizin Berlin, Campus Virchow Klinikum, Berlin, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Sebelin
authors.forename: Antje
authors.initials: A
authors.lastname: Schulzki
authors.forename: Peter M
authors.initials: PM
authors.lastname: Kloetzel
authors.forename: Bernd
authors.initials: B
authors.lastname: Dörken
authors.forename: Antonio
authors.initials: A
authors.lastname: Pezzutto
authors.forename: Marion
authors.initials: M
authors.lastname: Subklewe
mesh_terms: D000328:Adult; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003404:Creatinine / Q000097:blood; D016207:Cytokines / Q000097:blood; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007165:Immunosuppression Therapy / Q000379:methods*; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007371:Interferon-gamma / Q000097:blood; D016030:Kidney Transplantation / Q000276:immunology*; D018950:Lipopolysaccharide Receptors / Q000097:blood; D007959:Lymphocyte Culture Test, Mixed; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000166:cytology / Q000276:immunology; D016035:Pancreas Transplantation / Q000276:immunology*
chemical_list: D003404:Creatinine; D016207:Cytokines; D006442:Glycated Hemoglobin; D007166:Immunosuppressive Agents; D007371:Interferon-gamma; D018950:Lipopolysaccharide Receptors