Accepted Manuscript Review Donor-Specific Antibodies and liver transplantation Arnaud Del Bello, Nicolas Congy-Jolivet, Marie Danjoux, Fabrice Muscari, Nassim Kamar PII: DOI: Reference:
S0198-8859(16)30003-9 http://dx.doi.org/10.1016/j.humimm.2016.02.006 HIM 9708
To appear in:
Human Immunology
Received Date: Revised Date: Accepted Date:
21 September 2015 14 February 2016 18 February 2016
Please cite this article as: Bello, A.D., Congy-Jolivet, N., Danjoux, M., Muscari, F., Kamar, N., Donor-Specific Antibodies and liver transplantation, Human Immunology (2016), doi: http://dx.doi.org/10.1016/j.humimm. 2016.02.006
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Donor-Specific Antibodies and liver transplantation Arnaud Del Bello1,2, Nicolas Congy-Jolivet2,3,4, Marie Danjoux5, Fabrice Muscari2,6, Nassim Kamar1,2,7
1
Department of Nephrology and Organ Transplantation, CHU Rangueil, Toulouse, France
2
Université Paul Sabatier, Toulouse, France
3
Molecular Immunogenetics Laboratory, EA 3034, Faculté de Médecine Purpan, IFR150
(INSERM), France 4
Department of Immunology, CHU de Toulouse, Hôpital de Rangueil, CHU de Toulouse,
France 5
Department of Pathology, CHU Purpan, Toulouse, France
6
Department of Surgery and Liver Transplantation, Toulouse, France
7
INSERM U1043, IFR–BMT, CHU Purpan, Toulouse, France
Corresponding author: Arnaud Del Bello MD Department of Nephrology and Organ Transplantation, CHU Rangueil, TSA 50032, 31059 Toulouse Cedex 9, France Tel: +33 5 61 32 39 23; Fax: +33 5 61 32 39 89 E-mail: [email protected] Keywords: donor-specific antibodies, liver transplantation, antibody-mediated rejection, treatment, humoral response Short title:Anti-HLA antibodies and liver transplantation Financial disclosure: No conflicts of interest exist Abstract word count:175 Manuscript word count: 4118 Tables:2 Figures:2
Abstract In contrast to other types of organ transplantation, liver-transplant recipients used to be considered highly resistant to donor-specific antibodies (DSAs). Consequently, most transplant programs did not consider the presence of DSAs at transplantation or during the follow-up. However, since the early 1990s, antibody-mediated pathological lesions have been recognized in ABO-incompatible liver-transplant recipients. Recent data confirm the detrimental effect of preformed and de novo DSAs in ABO-compatible liver transplantation, with inferior clinical outcomes in patients presenting with circulating antibodies. Acute antibody-mediated rejection (AMR), plasma-cell hepatitis, biliary stricture, but also long-term complications, such as chronic rejection, liver ductopenia, and graft fibrosis, are now recognized to be associated with DSAs. Moreover, some non-HLA DSAs are suspected to induce graft dysfunction. Clinical, biological, and histological patterns within AMR need to be clarified. Treatment of these complications has yet to be defined. This article summarizes recent advances concerning the impact of preformed and de novo DSAs in liver transplantation, it defines the complications associated with DSAs, and discusses the potential strategies to manage patients with such complications.
Introduction Over the last decade, our knowledge on donor-specific alloantibodies (DSAs) in liver transplantation has dramatically changed. Since the early 1990s, several groups have reported increased graft-loss rates in orthotopic liver-transplant (OLT) recipients who had a positive crossmatch compared to OLT recipients with a negative crossmatch (1) (2) (3). However, over the next 20 years, DSAs were still considered to be clinically irrelevant to liver-allograft outcomes by most transplant teams. Recent advances in intensive care, surgical techniques, and immunosuppressive medications have markedly improved short- and intermediate-term liver-allograft survival (4). Nonetheless, long-term outcomes remain disappointing, as reported by the Scientific Registry of Transplantation (4), with a 10-year survival rate after liver transplantation of only 54%. The pathogenic role of DSAs in other types of organ transplant has been clearly established over the last decade. In kidney transplantation, DSAs are associated with acute and chronic antibody-mediated rejection (AMR), and early and late graft loss (5). Anti-HLA DSAs induce kidney-allograft microcirculation and macrovessel injury mainly through a complement-dependent pathway (6). Similar data are reported in heart (7), lung (8) and pancreas (9) transplantation. Improved understanding of the humoral response in organ-transplant recipients has been greatly helped by new sensitive assay in antibody detection. The single-antigen bead test had been developed, which uses purified antigens from recombinant lines that contain only a single HLA molecules (10). Since then, descriptions of the antibody subclasses and functional
tests (derived from the single-antigen bead tests) have been developed to separate complement binding and complement non-binding DSAs, thus improving our understanding of the risks of DSAs in graft recipients. Moreover, several teams have investigated the detrimental effects of antibodies directed against anti-angiotensin receptors (11), or directed against the major histocompatibility complex class-I chain-related gene A (MICA) (12), or glutathione-S-transferase T1 (GSTT1) (12). Herein, we review recent studies that have focused on the impact of preformed and de novo DSAs in liver-transplant recipients.
1.
Relative resistance to the humoral response of the liver: immunological
specificities in liver transplantation
Over the last decades, human liver allografts have been considered to be highly resistant to AMR caused by HLA antibodies compared to heart or kidney allografts (13). Several assumptions have been proposed to explain this difference: the dual (arterial and portal) afferent vasculature, and the greater liver mass compared with other organ transplants (14). Moreover, it was suggested that liver allografts were able to release soluble class-I MHC antigens into the recipient’s circulation (15), and that these antigens could form immune complexes with anti-class-I donor-specific allo-antibodies (14). Such immune complexes could be then absorbed and cleared by Kupffer cells. These cells were also suspected to contribute to hepatic resistance to AMR by phagocytosis of activated platelets, immune complexes, and activated complement components (14). Furthermore, the limited distribution of HLA class-II expression in the liver under stable conditions (16), and the marked hepatocyte regenerative capacity after injury, was also stressed (17).
More recently, some groups have proposed that an increase in Foxp3+CD25+CD4+ regulatory T cells could be involved in spontaneous liver acceptance (18). An imbalance between liver dendritic cells, apoptosis of liver graft-infiltrating cells, or recipient spleen CD8+ T cells is also suspected to contribute to the development of liver tolerance (19). Differences in expression of co-stimulation molecules are also suspected to be involved in this phenomenon (20). Polymorphisms of genes from the recipient's or donor's liver may also be involved in liver tolerance (21). However, these specificities do not fully prevent the risk of AMR. Experimental rat models have improved our understanding of AMR. Knechtle et al. (22) showed that significant sensitization could exceed the liver’s defenses against antibodies. During phases of aggression, such as acute cellular rejection (ACR) or viral and bacterial infection, strong induction of class-I and -II antigens has been noted by hepatocytes, bile-duct epithelium, and endothelial cells within liver transplants (23) (24) (25). Moreover, it was previously shown that the donor's Kupffer cells and interstitial dendritic cells were being gradually replaced during the post-transplant period by recipient accessory cells that expressed self-MHC molecules, which were then capable of presenting antigens to Tlymphocytes (26). All of these changes could then facilitate the development of an AMR. Despite a large liver mass, and its regenerative ability, some authors have shown an association between progressive fibrosis and the presence of DSAs in pediatric and adult liver-transplant recipients (27) (28). Furthermore, the beneficial balance of regulatory T cells, which leads to tolerance, can be easily broken with the use of, for example, immunosuppressive treatments (29). Overall, these data suggest that liver allografts have a relative resistance to AMR, but specific situations can override the liver’s natural resistance and defense mechanisms.
2.
AMR: clinical and histological findings, and treatment options 2.1
Definition of AMR
The first evidence that AMR could occur in liver allografts was observed more than 20 years ago in ABO-incompatible (ABOi) cadaveric, brain-dead, whole-organ donors. Demetris et al. reported, in 1988 (30), on the clinical and histopathological outcomes of 24 ABOi liver-transplant patients and compared these data with those from 38 ABO-compatible liver-transplant recipients. They found a higher rate of early graft failure (50% of portal tracts with bile-duct loss), and graft failure (46) (49) (50).
2.4 Treatment of acute AMR The published literature on the utilization of B-cell targeting agents in liver transplantation is limited, and the use of concomitant multimodality regimens makes the efficiency of each molecule difficult to ascertain (Table 1). Watson et al. (31) described the course of a patient treated for an isolated acute AMR with plasmapheresis IvIG and rituximab. Despite this treatment, the patient died with a graft failure, 115 days after the transplantation. Kamar et al. (51) described in 2008 2 cases of acute AMR in patients with preformed DSAs: one patient received steroid pulses, OKT3, plasmapheresis, and rituximab, but died rapidly after transplantation. One other patient was successfully treated with plasmapheresis, and rituximab, with a 9-month reevaluation biopsy showing complete resolution of the rejection (51). Kozlowski et al. (33) described the outcomes of three patients with acute AMR: two were treated with polyclonal antibodies, plasma exchange, and rituximab, and the third patient received the same treatment plus an OKT3. The results were disappointing: two patients died and the other patient needed re-transplantation. More recently, our team reported on a first series of five patients with maintenance transplantation who were treated for acute rejection with antibody-mediated participation with steroid pulses, plasma exchanges, rituximab (two patients), associated with OKT3 (one patient), as well as an improved maintenance therapy with high levels of tacrolimus, mycophenolic acid, and steroids (all five patients) (28). The overall results were good, with four patients alive at last the follow-up (median 53 [range: 3–55] months), which is a similar result to previously published case reports (51) (52).
Similarly, our group reported on another series of eight patients with acute rejection with antibody-mediated participation who were treated with rituximab associated with intravenous immunoglobulins (seven patients), plasma exchanges (five patients), and polyclonal antibodies (one patient) (35). The results were good for five patients, but two patients still had abnormal liver-test results, and one patient needed re-transplantation. In this series, one patient was treated with polyclonal antibodies and had a satisfactory outcome (35). Paterno et al. (48) reported on the use of bortezomib, with or without plasma exchange, for acute AMR in three liver-transplant recipients after the failed use of polyclonal antibodies/ steroid pulses (one patient), OKT3/steroid pulses/ polyclonal antibodies (one patient), and polyclonal antibodies/ rituximab (one patient). The results with bortezomib were encouraging concerning clinical and histological outcomes.
3.
Other manifestations associated with donor-specific HLA antibodies 3.1 Chronic rejection In a prospective study, O’Leary et al. (49) found that 92% of 39 patients who had a
biopsy-proven chronic rejection also presented with DSAs at diagnosis compared to 61% of control patients (p=0.003). Kaneku et al. (50) then showed that patients with chronic graft rejection presented more frequently with multiple IgG subclasses of DSAs in contrast to comparator patients (50% vs. 14%, p5 years post-transplantation (median 11[range: 5–20] years). They found a higher degree of fibrosis in patients with positive DSAs than in DSA-negative patients (mean fibrosis score 3.1 in the DSA-positive group vs. 1.1 in the DSA-negative group). Diffuse C4d-positive endothelial staining was significantly higher in the DSA-positive group and was associated with a higher fibrosis score (54) (table 2). Our group recorded similar data regarding adult liver-transplant recipients (after exclusion of patients with liver disease that could reoccur on the liver graft, or patients presenting with a viral infection), with a fibrosis Metavir score of 2.14±1 in patients with a DSA and of 0.9±0.9 in patients without a DSA (p=0.02) after a median time between a liver biopsy and transplantation of 90 (range: 7–190) and 50 (range: 7–201) months for patients with and without DSAs, respectively (28) (p=ns) (table 2). Accelerated fibrosis has been also shown in patients with hepatitis C virus (HCV). O’Leary et al. (55) reported on 507 HCV viremic
patients where preformed class-I [HR= 1.44, p=0.04] and -II [HR= 1.86, p
S0198-8859(16)30003-9 http://dx.doi.org/10.1016/j.humimm.2016.02.006 HIM 9708
To appear in:
Human Immunology
Received Date: Revised Date: Accepted Date:
21 September 2015 14 February 2016 18 February 2016
Please cite this article as: Bello, A.D., Congy-Jolivet, N., Danjoux, M., Muscari, F., Kamar, N., Donor-Specific Antibodies and liver transplantation, Human Immunology (2016), doi: http://dx.doi.org/10.1016/j.humimm. 2016.02.006
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Donor-Specific Antibodies and liver transplantation Arnaud Del Bello1,2, Nicolas Congy-Jolivet2,3,4, Marie Danjoux5, Fabrice Muscari2,6, Nassim Kamar1,2,7
1
Department of Nephrology and Organ Transplantation, CHU Rangueil, Toulouse, France
2
Université Paul Sabatier, Toulouse, France
3
Molecular Immunogenetics Laboratory, EA 3034, Faculté de Médecine Purpan, IFR150
(INSERM), France 4
Department of Immunology, CHU de Toulouse, Hôpital de Rangueil, CHU de Toulouse,
France 5
Department of Pathology, CHU Purpan, Toulouse, France
6
Department of Surgery and Liver Transplantation, Toulouse, France
7
INSERM U1043, IFR–BMT, CHU Purpan, Toulouse, France
Corresponding author: Arnaud Del Bello MD Department of Nephrology and Organ Transplantation, CHU Rangueil, TSA 50032, 31059 Toulouse Cedex 9, France Tel: +33 5 61 32 39 23; Fax: +33 5 61 32 39 89 E-mail: [email protected] Keywords: donor-specific antibodies, liver transplantation, antibody-mediated rejection, treatment, humoral response Short title:Anti-HLA antibodies and liver transplantation Financial disclosure: No conflicts of interest exist Abstract word count:175 Manuscript word count: 4118 Tables:2 Figures:2
Abstract In contrast to other types of organ transplantation, liver-transplant recipients used to be considered highly resistant to donor-specific antibodies (DSAs). Consequently, most transplant programs did not consider the presence of DSAs at transplantation or during the follow-up. However, since the early 1990s, antibody-mediated pathological lesions have been recognized in ABO-incompatible liver-transplant recipients. Recent data confirm the detrimental effect of preformed and de novo DSAs in ABO-compatible liver transplantation, with inferior clinical outcomes in patients presenting with circulating antibodies. Acute antibody-mediated rejection (AMR), plasma-cell hepatitis, biliary stricture, but also long-term complications, such as chronic rejection, liver ductopenia, and graft fibrosis, are now recognized to be associated with DSAs. Moreover, some non-HLA DSAs are suspected to induce graft dysfunction. Clinical, biological, and histological patterns within AMR need to be clarified. Treatment of these complications has yet to be defined. This article summarizes recent advances concerning the impact of preformed and de novo DSAs in liver transplantation, it defines the complications associated with DSAs, and discusses the potential strategies to manage patients with such complications.
Introduction Over the last decade, our knowledge on donor-specific alloantibodies (DSAs) in liver transplantation has dramatically changed. Since the early 1990s, several groups have reported increased graft-loss rates in orthotopic liver-transplant (OLT) recipients who had a positive crossmatch compared to OLT recipients with a negative crossmatch (1) (2) (3). However, over the next 20 years, DSAs were still considered to be clinically irrelevant to liver-allograft outcomes by most transplant teams. Recent advances in intensive care, surgical techniques, and immunosuppressive medications have markedly improved short- and intermediate-term liver-allograft survival (4). Nonetheless, long-term outcomes remain disappointing, as reported by the Scientific Registry of Transplantation (4), with a 10-year survival rate after liver transplantation of only 54%. The pathogenic role of DSAs in other types of organ transplant has been clearly established over the last decade. In kidney transplantation, DSAs are associated with acute and chronic antibody-mediated rejection (AMR), and early and late graft loss (5). Anti-HLA DSAs induce kidney-allograft microcirculation and macrovessel injury mainly through a complement-dependent pathway (6). Similar data are reported in heart (7), lung (8) and pancreas (9) transplantation. Improved understanding of the humoral response in organ-transplant recipients has been greatly helped by new sensitive assay in antibody detection. The single-antigen bead test had been developed, which uses purified antigens from recombinant lines that contain only a single HLA molecules (10). Since then, descriptions of the antibody subclasses and functional
tests (derived from the single-antigen bead tests) have been developed to separate complement binding and complement non-binding DSAs, thus improving our understanding of the risks of DSAs in graft recipients. Moreover, several teams have investigated the detrimental effects of antibodies directed against anti-angiotensin receptors (11), or directed against the major histocompatibility complex class-I chain-related gene A (MICA) (12), or glutathione-S-transferase T1 (GSTT1) (12). Herein, we review recent studies that have focused on the impact of preformed and de novo DSAs in liver-transplant recipients.
1.
Relative resistance to the humoral response of the liver: immunological
specificities in liver transplantation
Over the last decades, human liver allografts have been considered to be highly resistant to AMR caused by HLA antibodies compared to heart or kidney allografts (13). Several assumptions have been proposed to explain this difference: the dual (arterial and portal) afferent vasculature, and the greater liver mass compared with other organ transplants (14). Moreover, it was suggested that liver allografts were able to release soluble class-I MHC antigens into the recipient’s circulation (15), and that these antigens could form immune complexes with anti-class-I donor-specific allo-antibodies (14). Such immune complexes could be then absorbed and cleared by Kupffer cells. These cells were also suspected to contribute to hepatic resistance to AMR by phagocytosis of activated platelets, immune complexes, and activated complement components (14). Furthermore, the limited distribution of HLA class-II expression in the liver under stable conditions (16), and the marked hepatocyte regenerative capacity after injury, was also stressed (17).
More recently, some groups have proposed that an increase in Foxp3+CD25+CD4+ regulatory T cells could be involved in spontaneous liver acceptance (18). An imbalance between liver dendritic cells, apoptosis of liver graft-infiltrating cells, or recipient spleen CD8+ T cells is also suspected to contribute to the development of liver tolerance (19). Differences in expression of co-stimulation molecules are also suspected to be involved in this phenomenon (20). Polymorphisms of genes from the recipient's or donor's liver may also be involved in liver tolerance (21). However, these specificities do not fully prevent the risk of AMR. Experimental rat models have improved our understanding of AMR. Knechtle et al. (22) showed that significant sensitization could exceed the liver’s defenses against antibodies. During phases of aggression, such as acute cellular rejection (ACR) or viral and bacterial infection, strong induction of class-I and -II antigens has been noted by hepatocytes, bile-duct epithelium, and endothelial cells within liver transplants (23) (24) (25). Moreover, it was previously shown that the donor's Kupffer cells and interstitial dendritic cells were being gradually replaced during the post-transplant period by recipient accessory cells that expressed self-MHC molecules, which were then capable of presenting antigens to Tlymphocytes (26). All of these changes could then facilitate the development of an AMR. Despite a large liver mass, and its regenerative ability, some authors have shown an association between progressive fibrosis and the presence of DSAs in pediatric and adult liver-transplant recipients (27) (28). Furthermore, the beneficial balance of regulatory T cells, which leads to tolerance, can be easily broken with the use of, for example, immunosuppressive treatments (29). Overall, these data suggest that liver allografts have a relative resistance to AMR, but specific situations can override the liver’s natural resistance and defense mechanisms.
2.
AMR: clinical and histological findings, and treatment options 2.1
Definition of AMR
The first evidence that AMR could occur in liver allografts was observed more than 20 years ago in ABO-incompatible (ABOi) cadaveric, brain-dead, whole-organ donors. Demetris et al. reported, in 1988 (30), on the clinical and histopathological outcomes of 24 ABOi liver-transplant patients and compared these data with those from 38 ABO-compatible liver-transplant recipients. They found a higher rate of early graft failure (50% of portal tracts with bile-duct loss), and graft failure (46) (49) (50).
2.4 Treatment of acute AMR The published literature on the utilization of B-cell targeting agents in liver transplantation is limited, and the use of concomitant multimodality regimens makes the efficiency of each molecule difficult to ascertain (Table 1). Watson et al. (31) described the course of a patient treated for an isolated acute AMR with plasmapheresis IvIG and rituximab. Despite this treatment, the patient died with a graft failure, 115 days after the transplantation. Kamar et al. (51) described in 2008 2 cases of acute AMR in patients with preformed DSAs: one patient received steroid pulses, OKT3, plasmapheresis, and rituximab, but died rapidly after transplantation. One other patient was successfully treated with plasmapheresis, and rituximab, with a 9-month reevaluation biopsy showing complete resolution of the rejection (51). Kozlowski et al. (33) described the outcomes of three patients with acute AMR: two were treated with polyclonal antibodies, plasma exchange, and rituximab, and the third patient received the same treatment plus an OKT3. The results were disappointing: two patients died and the other patient needed re-transplantation. More recently, our team reported on a first series of five patients with maintenance transplantation who were treated for acute rejection with antibody-mediated participation with steroid pulses, plasma exchanges, rituximab (two patients), associated with OKT3 (one patient), as well as an improved maintenance therapy with high levels of tacrolimus, mycophenolic acid, and steroids (all five patients) (28). The overall results were good, with four patients alive at last the follow-up (median 53 [range: 3–55] months), which is a similar result to previously published case reports (51) (52).
Similarly, our group reported on another series of eight patients with acute rejection with antibody-mediated participation who were treated with rituximab associated with intravenous immunoglobulins (seven patients), plasma exchanges (five patients), and polyclonal antibodies (one patient) (35). The results were good for five patients, but two patients still had abnormal liver-test results, and one patient needed re-transplantation. In this series, one patient was treated with polyclonal antibodies and had a satisfactory outcome (35). Paterno et al. (48) reported on the use of bortezomib, with or without plasma exchange, for acute AMR in three liver-transplant recipients after the failed use of polyclonal antibodies/ steroid pulses (one patient), OKT3/steroid pulses/ polyclonal antibodies (one patient), and polyclonal antibodies/ rituximab (one patient). The results with bortezomib were encouraging concerning clinical and histological outcomes.
3.
Other manifestations associated with donor-specific HLA antibodies 3.1 Chronic rejection In a prospective study, O’Leary et al. (49) found that 92% of 39 patients who had a
biopsy-proven chronic rejection also presented with DSAs at diagnosis compared to 61% of control patients (p=0.003). Kaneku et al. (50) then showed that patients with chronic graft rejection presented more frequently with multiple IgG subclasses of DSAs in contrast to comparator patients (50% vs. 14%, p5 years post-transplantation (median 11[range: 5–20] years). They found a higher degree of fibrosis in patients with positive DSAs than in DSA-negative patients (mean fibrosis score 3.1 in the DSA-positive group vs. 1.1 in the DSA-negative group). Diffuse C4d-positive endothelial staining was significantly higher in the DSA-positive group and was associated with a higher fibrosis score (54) (table 2). Our group recorded similar data regarding adult liver-transplant recipients (after exclusion of patients with liver disease that could reoccur on the liver graft, or patients presenting with a viral infection), with a fibrosis Metavir score of 2.14±1 in patients with a DSA and of 0.9±0.9 in patients without a DSA (p=0.02) after a median time between a liver biopsy and transplantation of 90 (range: 7–190) and 50 (range: 7–201) months for patients with and without DSAs, respectively (28) (p=ns) (table 2). Accelerated fibrosis has been also shown in patients with hepatitis C virus (HCV). O’Leary et al. (55) reported on 507 HCV viremic
patients where preformed class-I [HR= 1.44, p=0.04] and -II [HR= 1.86, p
