title: The risk of polyomavirus-associated graft nephropathy is increased by a combined suppression of CD8 and CD4 cell-dependent immune effects.
abstract: Polyomavirus-associated graft nephropathy (PAN) has emerged as a significant risk factor for kidney graft loss. We analyzed intracellular cytokine responses for possible protective versus permissive immunologic effects on BK-virus replication. One hundred five renal transplant patients included in a prospective single-center study were randomized to receive cyclosporine mycophenolate mofetil (MMF) (CM: n = 31), tacrolimus (Tac)/MMF (TM: n = 32) or Tac/MMF with conversion to everolimus (TErl; n = 32). Ten patients were not randomized (NR) due to contraindications to MMF. The immunosuppressive therapy was monitored pre- and posttransplantation at 4, 12, and 24 months using triple fluorescence flow cytometry for intracellular interleukin (Il)-2 Il-4 and interferon (IFN)-γ production in phorbol myristate acetate- and lipopolysaccharide- stimulated lymphocyte cultures. BK viremia screening was performed by reverse-transcriptase polymerase chain reaction testing on days 0, 14, 30, 60, 90, 120, 180, 270, 360, and 720. Seven of 105 (6.7%) patients developed biopsy-proven PAN (CM: n = 1, TM: n = 3, TErl: n = 2, NR: n = 1), among whom 4 lost their grafts (TM: n = 1, TErl: n = 2, NR: n = 1). Twenty-one of 105 (20.0%) patients had documented BK viremia. BK viremia which preceded PAN in all cases, was significantly associated with TM immunosuppression: 4/31 (12.9%) CM: 11/32 (34.4%) TM; 5/32 (15.6%) TErl, and 1/10 (10.0%) NR patients (P = .034). BK-viremic patients showed significantly diminished CD8(+) T-cell Il-2 production at 120 days (P = .011) and 1 year posttransplantation (P = .014) compared with non-BK-viremic patients. Patients with PAN displayed significantly lower CD4(+) T-cell Il-4 responses at 1 and 2 years after transplantation (1 year: P = .007; 2 years: P = .001) with diminished IFN-γ responses at 1 year after transplantation (P = .011). Our analysis showed the incidence of BK viremia to be increased among patients with defective cytotoxic CD8(+) T-cell -dependent immune reactivity. Recipients who progressed from BK viremia to overt PAN showed an additional immunologic defect in CD4(+) T-cell function. Patients on a Tac- plus MMF-based immunosuppression were at higher risk to develop BK viremia.
authors.affiliation: Department of Internal Medicine, University of Giessen, Giessen, Germany. fabrice.renner@innere.med.uni-giessen.de
authors.forename: F C
authors.initials: FC
authors.lastname: Renner
authors.forename: H
authors.initials: H
authors.lastname: Dietrich
authors.forename: N
authors.initials: N
authors.lastname: Bulut
authors.forename: D
authors.initials: D
authors.lastname: Celik
authors.forename: E
authors.initials: E
authors.lastname: Freitag
authors.forename: N
authors.initials: N
authors.lastname: Gaertner
authors.forename: S
authors.initials: S
authors.lastname: Karoui
authors.forename: J
authors.initials: J
authors.lastname: Mark
authors.forename: C
authors.initials: C
authors.lastname: Raatz
authors.forename: R
authors.initials: R
authors.lastname: Weimer
authors.forename: A
authors.initials: A
authors.lastname: Feustel
mesh_terms: D001739:BK Virus / Q000302:isolation & purification*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D016572:Cyclosporine / Q000008:administration & dosage; D000068338:Everolimus; D005434:Flow Cytometry; D006084:Graft Rejection / Q000209:etiology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage; D016030:Kidney Transplantation; D009173:Mycophenolic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives; D027601:Polyomavirus Infections / Q000150:complications* / Q000276:immunology / Q000821:virology; D011446:Prospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D020123:Sirolimus / Q000008:administration & dosage / Q000031:analogs & derivatives; D016559:Tacrolimus / Q000008:administration & dosage; D014766:Viremia / Q000150:complications / Q000276:immunology / Q000821:virology
chemical_list: D007166:Immunosuppressive Agents; D016572:Cyclosporine; D000068338:Everolimus; D009173:Mycophenolic Acid; D020123:Sirolimus; D016559:Tacrolimus