Acceptance of an ABO-incompatible mismatched (AB(+) to O(+)) liver allograft with the use of daclizumab and mycophenolate mofetil

ABO Incompatible Liver Transplantation in Children: A 20 Year Experience from Centres in the TransplantChild European Reference Network

An increasing number of AB0-incompatible (AB0i) liver transplantations (LT) are being undertaken internationally in recent years due to organ shortages and the need for urgent transplantation. The aim of our study was establish the value of ABOi LT from available retrospective results of AB0i pediatric liver transplantations performed in European reference centers now belonging to the TransplantChild, European Reference Network (ERN). Data from medical records were analyzed, including demographic data, diagnosis, urgency of transplantation, time on the waiting list, PELD/MELD score, desensitization procedures, immunosuppression, selected post-transplant complications, and patient and graft survival. A total of 142 patients (pts) with transplants between 1986 and 2018 in 8 European transplant centers were included in the study. The indications for liver transplantation were: cholestatic diseases in 62 pts, acute liver failure in 42 pts, and other conditions in the remaining 38 pts. Sixty-six patients received grafts from living donors, and seventy-six received grafts from deceased donors. Both patient and graft survival were significantly affected by deceased donor type, urgent transplantation, and the development of vascular complications. In the multivariate analysis, vascular complications had a negative impact on patient and graft survival, while a longer time from the first AB0i LT in the study showed better results, suggesting an international learning experience. In conclusion, we believe that AB0i LT in children is now a safe procedure that may be adopted more readily in children.

Emergency ABO-incompatible liver transplant secondary to fulminant hepatic failure: outcome, role of TPE and review of the literature

The increasing demand for solid organ transplants has brought to light the need to utilize organs in critical situations despite ABO-incompatibility. However, these transplantations are complicated by pre-existing ABO antibodies which may be potentially dangerous and makes the transplantation prone to failure due to rejection with resulting necrosis or intrahepatic biliary complications. We report the clinical outcome of an emergency ABO-incompatible liver transplant (due to fulminant hepatic failure with sudden and rapidly deteriorating mental status) using a modified therapeutic plasma exchange (TPE) protocol. The recipient was O-positive with an initial anti-B titer of 64 and the cadaveric organ was from a B-positive donor. The patient underwent initial TPE during the peri-operative period, followed by a series of postoperative daily TPE, and later a third series of TPE for presumptive antibody-mediated rejection. The latter two were performed in conjunction with the use of IVIg and rituximab. The recipient's anti-B titer was reduced and maintained at 8 or less 8 months post-op. However, an elevation of transaminases 3 months post-transplant triggered a biopsy which was consistent with cellular rejection and with weak C4d positive staining suggestive of antibody mediated rejection. Additional plasma exchange procedures were performed. The patient improved rapidly after modification of her immunosuppression regimen and treatment with plasma exchange. This case illustrates that prompt and aggressive plasma exchange, in conjunction with immunosuppression, is a viable approach to prevent and treat antibody mediated transplant rejection in emergency ABO-incompatible liver transplant.

Successful long-term outcome of ABO-incompatible liver transplantation using antigen-specific immunoadsorption columns

ABO-incompatible (ABO-I) liver transplantation has been performed essentially in patients with acute liver failure awaiting an urgent liver transplantation. Early results with ABO-I liver transplantation were disappointing with a very low graft survival rate (20-50%). The main risk is the occurrence of severe humoral and cellular rejection, vascular thrombosis, and biliary complications. In order to avoid humoral rejection and improve graft survival, total plasma exchange in combination with an intense immunosuppressive regimen has been proposed to decrease hemagglutinin titers in ABO-I liver grafts. In some centers, this regimen was associated with splenectomy, phototherapy, and portal or arterial intrahepatic infusion therapy; however, as these patients are at high risk of sepsis, a selective approach using antigen-specific immunoadsorption with immunoadsorbent columns has been successfully proposed for ABO-I living donor kidney transplantation. Few cases have been reported following liver transplantation. We report our recent experience with three adult patients (two patients with acute liver failure, and one with severe cirrhosis and hepatic encephalopathy) transplanted in an emergency situation with an ABO-I liver graft and managed with the use of GlycoSorb ABO immunoadsorbent columns and a quadruple immunosuppressive regimen with preservation of the spleen. Eight sessions were performed in the three patients. Antigen-specific immunoadsorption greatly lowered the anti-A hemagglutinin titers. None of the three patients developed acute humoral or cellular rejection. Two patients are alive at 1.5 and 3 years follow-up with a normally functioning graft. The third patient died with a functioning graft, one month after the transplantation, from septic complications.

ABO-mismatch adult living donor liver transplantation using antigen-specific immunoadsorption and quadruple immunosuppression without splenectomy

ABO-incompatible (ABO-I) liver transplantation is a controversial issue because of the generally less favorable outcome as compared to compatible transplants. Encouraging results have been shown by the introduction of new strategies to reduce posttransplant-specific hemagglutinin (HA) titers with plasmapheresis, reinforced immunosuppression (IS), and the use of splenectomy. We describe a new protocol consisting of daclizumab (DAC) induction, mycophenolate mofetil (MMF)/tacrolimus (TAC)/steroids without splenectomy. Five recipients (mean age of 47 +/- 14 yr) undergoing ABO-I living donor liver transplantation (LDLT) were included in this protocol. Immunoadsorbent columns (Glycosorb ABO) were used for antigen-specific immunoadsorption (ASI). The median follow-up was 18.5 +/- 10.5 months. ASI was very efficient in lowering HA titers (mean log(2) immunoglobulin [Ig] M [IgM] and IgG values before and after ASI were 5.9 +/- 2.8 and 1.2 +/- 1.4 [P= 0.0038] and 6.5 +/- 2.3 and 1.1+/- 1.9, respectively [P= 0.0001]). Persisting low HA titers were observed over time. No sepsis nor cytomegalovirus infection episodes were recorded. Acute cellular rejection (ACR) occurred in 1 recipient responding to steroid pulse therapy. Two grafts were lost in 2 patients due to technical failure during the first postoperative month. We conclude that ASI using Glycosorb ABO, quadruple immunosuppression including DAC and MMF provide high efficiency to lower HA titers over time, avoiding the need for splenectomy. ABO-I LDLT can be performed with this adapted IS protocol.

Successful ABO-incompatible pediatric liver transplantation utilizing standard immunosuppression with selective postoperative plasmapheresis

Transplanting blood group A, B, or O (ABO)-incompatible (ABO-I) liver grafts has resulted in lower patient and graft survival with an increased incidence of vascular and biliary complications and rejection. We report that, without modification of our standard immunosuppression protocol, crossing blood groups is an acceptable option for children requiring liver transplantation. In our study, ABO-I liver grafts -- regardless of recipient age -- have comparable long-term survival (mean follow-up of 3.25 yr) with ABO-compatible grafts without any difference in rejection, vascular or biliary complications. From January 1, 1999 to October 1, 2005, we studied 138 liver transplants in 121 children: 16 (13.2%) received an ABO incompatible liver allograft. One-year actuarial patient survival for ABO-matched grafts vs. ABO-I grafts was 93.0% and 100%, respectively, whereas graft survival was 83.4% and 92.3%. Additionally, 6 of 16 (37.5%) ABO-I transplanted children had 8 rejection episodes, whereas 47 patients (44.8%) had 121 rejection episodes in the ABO-compatible group. There were no vascular complications and 2 biliary strictures in the ABO-I group. Plasmapheresis was not used for pretransplantation desensitization and was only required in 1 posttransplantation recipient. No child was splenectomized. Six of the 16 children were older than 13 yr of age, suggesting the possibility of successfully expanding this technique to an older population. In conclusion, our outcomes may support the concept of using ABO-I grafts in a more elective setting associated with split and living donor liver transplants.

ABO-incompatible liver transplantation: a new therapeutic option for patients with acute liver failure in Chile

Different ways have been suggested to expand donor numbers for liver transplantation. Transplantation using ABO-incompatible hepatic grafts has recently been a controversial issue due to the high risk of hyperacute rejection mediated by preformed anti-ABO antibodies. We report three patients with acute liver failure who were transplanted with ABO-incompatible livers: A to O in two patients and A to B in one case. We used pre- and posttransplant total plasma exchange, splenectomy, and triple immunosuppression. All three patients are alive; one graft was lost, probably secondary to thrombotic microangiopathy with low isohemagglutinin titers of 1:8. One patient developed acute cellular rejection that was reversed with a bolus of methylprednisolone. No antibody-mediated rejection occurred. Financial and infectious considerations have to be considered. In our series, the final liver transplantation cost was higher than average for acute liver failure. Plasmapheresis has the highest cost of all the additional procedures. ABO-incompatible liver transplantation, because of the splenectomy it requires, has been associated with more infections due to encapsulated organisms. However, with splenectomy in our three patients, none had infections due to these bacteria. In our country, we do not consider ABO-incompatible liver transplantation as a first-line option, except for highly selected patients.

Successful use of anti-CD20 monoclonal antibody (rituximab) for ABO-incompatible living-related liver transplantation

BACKGROUND

Humoral rejection after ABO-incompatible liver transplantation often causes graft loss and a life-threatening situation. We used rituximab, which can eliminate B cells highly selectively, as an additional therapy for ABO-incompatible living-related liver transplantation.

CASES

Patient 1 was a 1-year-old girl with biliary atresia. Her blood type was O, and the donor's was A. She underwent two plasma exchanges before liver transplantation and had triple immunosuppressants (mycophenolate mofetil, tacrolimus, and methylprednisolone). She was diagnosed with humoral rejection by needle biopsy on postoperative day 6. Rituximab was used for 3 days at 375, 187, and 187 mg/m(2) and successfully reduced the antibody titer, transaminase, and CD19(+) cells count in peripheral blood lymphocytes. The patient has not had any severe rejection, infection, or serious complications 2 years posttransplantation. Patient 2 was a 42-year-old woman with primary biliary cirrhosis. The blood type was O, and the donor's was B. She received three plasma exchanges, triple immunosuppressants, splenectomy, intraarterial anticoagulant therapy, and rituximab (375 mg/m(2) immediately after transplantation). The titer and CD19(+) cells count remained persistently low throughout the recovery course. She did not develop humoral rejection 1 year after transplantation.

CONCLUSIONS

Rituximab efficiently reduces anti-ABO antibody titer by selectively eliminating B cells and is safe and effective against humoral rejection after ABO-incompatible liver transplantation.

Plasma adsorption in critical care

Plasmapheresis therapies such as plasma exchange (PE), double filtration plasmapheresis (DFPP), or immunoadsorption plasmapheresis (IAPP) have become therapeutic tools in critical care. PE or DFPP are limited by their non- or semiselective removal of all plasma components. Replacement fluids such as fresh frozen plasma and albumin are necessary during PE or DFPP. There is the risk of infection and allergic reactions whenever such fluids are used. On the other hand, IAPP is superior to PE and DFPP because it does not require any replacement fluid. There has been development of many adsorbent columns used for removing specific pathogenic substances, and patients with various kinds of critical illness have been treated with IAPP. However, IAPP can be applied only for certain diseases because of the limitations of the commercially available columns. It is concluded that the development of new adsorption therapy may improve the high mortality and morbidity rate in critically ill patients.

Human leukocyte differentiation antigens as therapeutic targets: the CD molecules and CD antibodies

The cell membrane presents an attractive target in a number of different disease situations. Most obviously, malignant cells may be killed by damaging their cell membranes. There are also more subtle, though effective, ways of rendering cells harmless by engaging proteins at the cell surface. The cells of the immune system may be targeted, for example to stop a damaging immune reaction, such as acute inflammation or rejection of a transplanted organ. If we are to make the best use of the opportunities to modulate disease by targeting the cell membrane, we need a detailed understanding of the many proteins, glycoproteins and glycolipids that are attached to or inserted in the cell membrane. The CD (cluster of differentiation) Workshops, more properly known as the HLDA (Human Leukocyte Differentiation Antigens) Workshops have, since 1982, focussed on the study of the membrane molecules of leukocytes, including the major cells of the immune system and malignant cells derived from them. The scope has extended to molecules on endothelium which are important in interaction with leukocytes. Many of the molecules characterised as leukocyte antigens are also expressed on other tissue. The approaches developed by the HLDA Workshops are useful in the study of the molecular composition and function of cells of other organ systems. Some of the antibodies produced in order to study the CD molecules have proved useful as therapeutic agents. This review describes the CD system, how it has developed and what it means and introduces the field of therapy based on antibodies against CD or similar molecules. The author is responsible for organising the next (8th) HLDA Workshop and invites readers to suggest ways in which the therapeutic relevance of the Workshop may be enhanced.