Cyclosporine and tacrolimus have inhibitory effects on toll-like receptor signaling after liver transplantation

Authors


  • Jessica Howell contributed to the study design, laboratory experiments (performance and design), acquisition of data, analysis and interpretation of data, statistical analysis, and manuscript writing. Rohit Sawhney contributed to the laboratory experiments, acquisition of data, and manuscript drafting. Adam Testro contributed to the laboratory protocol and provided assistance with the experimental design. Narelle Skinner provided laboratory expertise and assistance with the experimental design. Paul Gow contributed to the study supervision, study design, and manuscript drafting. Peter Angus contributed to the study supervision, study design, and manuscript drafting. Dilip Ratnam provided assistance with the experimental design. Kumar Visvanathan contributed to the study supervision, study design, and manuscript drafting and provided laboratory expertise and assistance with the experimental design.

  • None of the authors have any disclosures to make relevant to this study or article.

  • Funding for this study was provided by nonspecific Innate Immune Laboratory educational funds, which are supported by Monash University (Melbourne Australia). Jessica Howell received scholarship funds for a stipend from the Gastroenterological Society of Australia.

Address reprint requests to Jessica Howell, Ph.D., Liver Transplant Unit, Austin Hospital, Studley Road, Heidelberg 3084, Melbourne, Victoria, Australia. Telephone: 61 3 94965000; FAX: 61 3 94963487; E-mail: manukascarlet@yahoo.com

Abstract

Toll-like receptors (TLRs) play a key role in transplantation biology. The effect of immunosuppression on TLR function after liver transplantation is unknown. Peripheral blood mononuclear cells (PBMCs) from 113 post–liver transplant patients and 13 healthy controls were stimulated with TLR-specific ligands [lipopolysaccharide (TLR4), pan-3-cys (P3C) (TLR2), Poly (I:C) (PIC) (TLR3), R848 (TLR7/8), and CpG (TLR9)] for 24 hours. PBMCs from 5 healthy controls were also cultured with therapeutic concentrations of cyclosporine A (CYA) and tacrolimus (TAC). Cytokine production was measured with enzyme-linked immunosorbent assays and flow cytometry. PBMCs from patients on calcineurin inhibitors after liver transplantation produced less interleukin-6 (IL-6) and tumor necrosis factor α (TNFα) in response to TLR2 stimulation (IL-6: P=0.02; TNFα: P=0.01), TLR4 stimulation (IL-6: P=0.02; TNFα: P=0.01), and TLR7/8 stimulation (IL-6: P=0.02; TNFα: P=0.02), compared with healthy controls. Both CD56bright and CD56dim natural killer (NK) cells from patients on calcineurin inhibitors also produced less interferon-γ (IFNγ) with TLR7/8 stimulation compared with healthy controls (CD56bright: P=0.002; CD56dim: P=0.004). Similar findings were demonstrated in healthy PBMCs cultured with CYA (PBMCs: TLR2, IL-6: P=0.005; TLR4, IL-6: P=0.03, TNFα: P=0.03; TLR7/8, IL-6: P=0.02, TNFα: P=0.01; CD56dim NK cells: TLR7/8, IFNγ: P=0.03). TAC impaired TLR4-mediated IL-6 and TNFα production by PBMCs (IL-6; P = 0.02; TNFα P = 0.009). In conclusion, patients on calcineurin inhibitors had impaired inflammatory cytokine production in response to TLR2, TLR4, and TLR7/8 stimulation compared comparison with healthy controls. Importantly, TAC and CYA appear to have different effects on TLR signaling. Impaired TLR function has important repercussions for risk of infection, graft rejection, and disease recurrence after transplantation, and the different immunosuppressive profiles of CYA and TAC may guide the choice of therapy to improve disease outcomes. Liver Transpl 19:1099-1107, 2013. © 2013 AASLD.

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