[Frontiers in Bioscience E4, 2121-2130, January 1, 2012]

Humoral immunity-mediated chronic rejection in liver transplantation is associated with predominant IL-10 expression

Renhua Wan1, Liping Tang1, Renfeng Shan1, Linxiang Zeng2, Haimin Chen1, Lianghui Gao1

1Department of Hepatobiliary and Pancreatic Surgery and Center of Organ Transplantation, The First Affiliated Hospital of Nanchang University, Jiangxi, China, 2Department of Respiratory, The Second Affiliated Hospital of Nanchang University, Jiangxi, China

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and methods
3.1. Experimental animals
3.2. Liver transplantation and anti-IL-10 mAb treatments
3.3. In vitro assay
3.4. Cytokine and pro-fibrosis genetic factor ELISA
3.5. Flow cytometry for donor-specific antibodies
3.6. C4d immunohistochemistry and scoring of C4d staining
3.7. TUNEL assay
3.8. Statistical analysis
4. Results
4.1. Predominant expression of serum IL-10 in chronic allograft liver rejection
4.2. Involvement of donor-specific antibodies and C4d deposition in chronic allograft liver rejection
4.3. Donor-specific antibody induced apoptosis of donor liver cells and expression of pro-fibrosis factors in vitro
4.4. Donor-specific antibody level is positively correlated with IL-10 expression in chronic allograft liver rejection
4.5. Humoral rejection is inhibited upon IL-10 blockade
5. Discussion
6. Acknowledgements
7. References

1. ABSTRACT

Chronic rejection is a major cause of graft dysfunction and retransplantation after liver allotransplantation. Recent studies have implicated humoral response in this chronic rejection reaction. However, the manner in which humoral response is activated has not been fully investigated. In the present study, we address this question using our previously established chronic allograft liver rejection model induced by low-dose immunosuppressive cyclosporine (CsA) following Dark Agouti (DA) to Brown Norway (BN) liver transplantation. High-level donor-specific antibodies (IgG1 isotype), C4d deposition and histological graft damage indicated the involvement of humoral rejection in this chronic rejection reaction. In vitro assay showed that alloantibodies from pre-sensitized BN recipients induced apoptosis of bile ductal cells isolated from donor livers and the production of pro-fibrosis factors (TGF-beta, PDGF and FGF). Statistical analysis showed that the serum level of IL-10 was positively correlated with that of donor-specific antibodies (IgG1 isotype). Blockade of IL-10 in vivo down-regulated the level of donor-specific antibodies and ameliorated the outcome of chronic rejection. This suggests that humoral response in chronic allograft liver rejection is associated with Th2 type cytokine IL-10 and that Th2 response might promote chronic rejection by inducing a humoral response.