Refractory humoral cardiac allograft rejection successfully treated with a single dose of rituximab

A Case of Daratumumab-Induced Significant Decrease in Donor-Specific HLA Antibodies and Remission Induction Before Haploidentical Stem Cell Transplantation in a Refractory B-ALL Patient

Objective:

To explore the method of eliminating donor-specific anti-HLA antibodies (DSA) in haploidentical stem cell transplantation (haplo-SCT).

Methods:

We present a refractory B-cell acute lymphoblastic leukemia (ALL) patient who had strongly positive DSA, but had no human leukocyte antigen–matched donor. Although CD38 expression on leukemia cells was negative, daratumumab combined with etoposide and venetoclax therapy was chosen for her.

Results:

She achieved a significant decrease in DSA levels and complete remission on the combination therapy with daratumumab. She then received a haplo-SCT from a daughter as a donor and had a successful engraftment of donor stem cell. In haplo-SCT, strongly positive DSA levels, directed against donor HLA antigens, could be significantly reduced by daratumumab therapy before transplantation and successfully bridge subsequent haplo-SCT.

Conclusion:

Although CD38 expression is negative in leukemia cells, refractory B-ALL patients may still benefit from combination therapy with daratumumab. We need further clinical observation.

Novel Immunosuppression in Solid Organ Transplantation

Solid organ transplantation and survival has improved tremendously in the last few decades, much of the success has been attributed to the advancements in immunosuppression. While steroids are being replaced and much of the immunosuppressive strategies focus on steroid free regimens, novel agents have introduced in the induction, maintenance, and treatment of acute rejection phase. MTOR inhibitors have helped with the renal sparing side effect from the calcineurin inhibitors, newer agents such as rituximab have decreased the incidence of donor-specific antibodies which led to decreased incidence of acute rejection reactions. In this chapter we discuss the newer therapies directed specifically for solid organ transplantation.

Sensitization in Heart Transplantation: Emerging Knowledge: A Scientific Statement From the American Heart Association

Sensitization, defined as the presence of circulating antibodies, presents challenges for heart transplant recipients and physicians. When present, sensitization can limit a transplantation candidate’s access to organs, prolong wait time, and, in some cases, exclude the candidate from heart transplantation altogether. The management of sensitization is not yet standardized, and current therapies have not yielded consistent results. Although current strategies involve antibody suppression and removal with intravenous immunoglobulin, plasmapheresis, and antibody therapy, newer strategies with more specific targets are being investigated.

The European Society for Blood and Marrow Transplantation (EBMT) Consensus Guidelines for the Detection and Treatment of Donor-specific Anti-HLA Antibodies (DSA) in Haploidentical Hematopoietic Cell Transplantation

Haploidentical donors are now increasingly considered for transplantation in the absence of HLA-matched donors or when an urgent transplant is needed. Donor-specific anti-HLA antibodies (DSA) have been recently recognized as an important barrier against successful engraftment of donor cells, which can affect transplant survival. DSA appear more prevalent in this type of transplant due to higher likelihood of alloimmunization of multiparous females against offspring's HLA antigens, and the degree of mismatch. Here we summarize the evidence for the role of DSA in the development of primary graft failure in haploidentical transplantation and provide consensus recommendations from the European Society for Blood and Marrow Transplant Group on testing, monitoring, and treatment of patients with DSA receiving haploidentical hematopoietic progenitor cell transplantation.

Rituximab Therapy for Rejection in Pediatric Heart Transplant

OBJECTIVES

Humoral rejection is the B-cell-mediated production of immunoglobulin G antibody against the transplanted heart. Antibody-mediated rejection may be resistant to standard immunosuppressive therapy and is associated with high mortality and graft loss. Rituximab can be used to treat antibody-mediated rejection in heart transplant recipients. This retrospective study describes our experience with rituximab treatment in children with heart transplants.

MATERIALS AND METHODS

We present 7 pediatric patients with antibody-mediated rejection who were treated with plasma exchange and rituximab therapy. Rituximab was given at a dose of 375 mg/m2 by slow infusion in the intensive care unit after 5 days of plasmapheresis, in addition to a conventional regimen consisting of steroids, mycophenolate mofetil, and tacrolimus. The peripheral blood count and sodium, potassium, serum urea nitrogen, creatinine, aspartate aminotransferase, and alanine aminotransferase levels were measured in all patients before and after treatment.

RESULTS

Seven patients were treated with plasma exchange and rituximab. We repeated this therapy in 5 patients because of refractoriness or recurrent rejection. After diagnoses of antibody-mediated rejection, 4 patients died within 6 months (mortality rate of 57.1%). We did not observe any adverse effects or complications related to rituximab.

CONCLUSIONS

Rituximab can be used in humoral rejection after pediatric heart transplant. However, the success of the treatment is controversial, and further study is needed to find an effective treatment for antibody-mediated rejection and steroid-resistant cellular rejection in children.

Donor Specific Anti-HLA Antibody and Risk of Graft Failure in Haploidentical Stem Cell Transplantation

Outcomes of allogeneic hematopoietic stem cell transplantation (AHSCT) using HLA-half matched related donors (haploidentical) have recently improved due to better control of alloreactive reactions in both graft-versus-host and host-versus-graft directions. The recognition of the role of humoral rejection in the development of primary graft failure in this setting has broadened our understanding about causes of engraftment failure in these patients, helped us better select donors for patients in need of AHSCT, and developed rational therapeutic measures for HLA sensitized patients to prevent this unfortunate event, which is usually associated with a very high mortality rate. With these recent advances the rate of graft failure in haploidentical transplantation has decreased to less than 5%.

Improving survival during heart transplantation: diagnosis of antibody-mediated rejection and techniques for the prevention of graft injury

The diagnosis of antibody-mediated rejection (AMR) has presented a challenge due to the pleiomorphic immunologic responses that represent the condition. A consensus with regard to its pathological diagnosis continues to evolve. Due to an increasing number of sensitized patients undergoing heart transplantation, its incidence appears to be on the rise and the condition is associated with worse outcomes than acute cellular rejection. Treatment of AMR is also more difficult and response to increases in conventional immunosuppression is often limited. Risk factors for AMR include the use of ventricular assist devices, prior exposure to blood products, allografts and multiparity. Detection of alloantibodies with a high specificity and sensitivity allows risk stratification of recipients at potential risk of AMR. Desensitization and AMR treatment strategies are focused on several therapeutic targets, including suppression of T and B cells and elimination or inhibition of circulating antibodies.

Rapid reduction in donor-specific anti-human leukocyte antigen antibodies and reversal of antibody-mediated rejection with bortezomib in pediatric heart transplant patients

BACKGROUND

High titer donor-specific antibodies (DSA) and positive crossmatch in cardiac transplant recipients is associated with increased mortality from antibody-mediated rejection (AMR). Although treatment to reduce anti-human leukocyte antigen antibodies using plasmapheresis, intravenous immunoglobulin, and rituximab has been reported to be beneficial, in practice these are often ineffective. Moreover, these interventions do not affect the mature antibody producing plasma cell. Bortezomib, a proteasome inhibitor active against plasma cells, has been shown to reduce DSA in renal transplant patients with AMR. We report here the first use of bortezomib for cardiac transplant recipients in four pediatric heart recipients with biopsy-proven AMR, hemodynamic compromise, positive crossmatch, and high titer class I DSA.

METHODS

Patients received four intravenous dose of bortezomib (1.3 mg/m(2)) over 2 weeks with plasmapheresis and rituximab. DSA specificity and strength (mean fluorescence intensity) was determined with Luminex. All had received previous treatment with plasmapheresis, intravenous immunoglobulin, and rituximab that was ineffective.

RESULTS

AMR resolved in all patients treated with bortezomib with improvement in systolic function, conversion of biopsy to C4d negative in three patients and IgG negative in one patient, and a prompt, precipitous reduction in DSAs. In three patients who received plasmapheresis before bortezomib, plasmapheresis failed to reduce DSA. In one case, DSA increased after bortezomib but decreased after retreatment.

CONCLUSIONS

Bortezomib reduces DSA and may be an important adjunct to treatment of AMR in cardiac transplant recipients. Bortezomib may also be useful in desensitization protocols and in prevention of AMR in sensitized patients with positive crossmatch and elevated DSA.

Phenotypic evaluation of B-cell subsets after rituximab for treatment of acute renal allograft rejection in pediatric recipients

BACKGROUND

Recently published pediatric trial of Rituximab for the treatment of CD20+ acute renal allograft rejection (AR) demonstrated transient depletion of circulating/intragraft B cells (Zarkhin et al., Am J Transplant 2008; 8: 2607). In this study, we have evaluated phenotypic definition of circulating B-cell subsets before and after standard of care and B-cell depletional AR therapies.

METHODS

We assessed peripheral B cells by flow cytometry at the time of AR and after AR treatment in 35 pediatric renal transplant recipients: 17 patients with AR who received Rituximab (R-AR; n=11) or steroid pulsing (S-AR; n=6), 18 stable patients with stable graft function with (iSTA; n=10) or without interval infection (hSTA; n=8), and 3 healthy volunteers.

RESULTS

Infections increased memory (P=0.02) and CD19+/CD27⁻/IgD⁻ double negative (DN) B cells (P=0.02) and decreased naive B cells (P=0.01) in iSTA group compared to hSTA patients. Decrease in naive/memory B cells ratio at AR was observed compared with hSTA patients (P=0.01). One year after AR treatment, S-AR patients had persistently lower naive/memory B-cell ratio (P=0.01) and higher DN B cells (P=0.0001) than hSTA patients, whereas after R-AR treatment naive/memory B-cell ratio (P=0.6) and DN B cells (P=0.13) recovered to levels of hSTA patients. R-AR patients with sustained AR resolution (n=8) had trend toward better graft survival (P=0.06) and higher naive B cells (P=0.004) than R-AR relapsers (n=3).

CONCLUSIONS

Increase in circulating memory B cells was seen in pediatric patients at AR. B cells persist as memory after S-AR treatment, whereas Rituximab resulted in repopulation of mostly naive B cells. The heterogeneity in B-cells reconstitution after rejection therapies deserves further investigation as a possible means to follow the clinical and immunologic outcomes of graft rejection.

Management of the sensitized adult heart transplant candidate

Heart transplant recipients sensitized to human leukocyte antigens comprise a challenging subgroup of patients. Sensitization has been associated with a variety of effects that determine short-term and long-term outcomes. These include a higher rate of acute rejection and graft loss, and a heightened risk for developing cardiac allograft vasculopathy. Because of improvements in both tissue typing and immunomodulatory therapies coupled with the growing population receiving mechanical circulatory support/LVAD, the percent of sensitized patients listed for heart transplantation has increased, inflicting a greater burden to the already scarce donor pool. Despite these potentially adverse developments, pre-transplant immunologic management has resulted in decreased waiting times and outcomes that were not possible over 10 yr ago. The following review will focus on the contemporary management of the sensitized heart transplant candidate and highlight therapies that have allowed the successful transplantation of this growing and challenging patient population, including several approaches in development.

Management of allosensitized cardiac transplant candidates

Cardiac transplantation remains the best treatment in patients with advanced heart failure with a high risk of death. However, an inadequate supply of donor hearts decreases the likelihood of transplantation for many patients. Ventricular assist devices (VADs) are being increasingly used as a bridge to transplantation in patients who may not survive long enough to receive a heart. This expansion in VAD use has been associated with increasing rates of allosensitization in cardiac transplant candidates. Anti-HLA antibodies can be detected before transplantation using different techniques. Complement-dependent lymphocytotoxicity assays are widely used for measurement of panel-reactive antibody (PRA) and for crossmatch purposes. Newer assays using solid-phase flow techniques feature improved specificity and offer detailed information concerning antibody specificities, which may lead to improvements in donor-recipient matching. Allosensitization prolongs the wait time for transplantation and increases the risk of post-transplantation complications and death; therefore, decreasing anti-HLA antibodies in sensitized transplant candidates is of vital importance. Plasmapheresis, intravenous immunoglobulin, and rituximab have been used to decrease the PRA before transplantation, with varying degrees of success. The most significant post-transplantation complications seen in allosensitized recipients are antibody-mediated rejection (AMR) and cardiac allograft vasculopathy (CAV). Often, AMR manifests with severe allograft dysfunction and hemodynamic compromise. The underlying pathophysiology is not fully understood but appears to involve complement-mediated activation of endothelial cells resulting in ischemic injury. The treatment of AMR in cardiac recipients is largely empirical and includes high-dose corticosteroids, plasmapheresis, intravenous immunoglobulin, and rituximab. Diffuse concentric stenosis of allograft coronary arteries due to intimal expansion is a characteristic of CAV. Its pathophysiology is unclear but may involve chronic complement-mediated endothelial injury. Sirolimus and everolimus can delay the progression of CAV. In some nonsensitized cardiac transplant recipients, the de novo formation of anti-HLA antibodies after transplantation may increase the likelihood of adverse clinical outcomes. Serial post-transplantation PRAs may be advisable in patients at high risk of de novo allosensitization.

Antibody-mediated rejection: treatment alternatives and outcomes

Over the past 10 years, thanks to the development of sensitive methods of antibody detection and markers of antibody injury such as C4d staining, the role of anti-human leukocyte antigen (HLA) and non-HLA alloantibodies as effectors of acute and chronic immune allograft injury has been revisited. Antibody-mediated rejection (AMR) defines all allograft rejection caused by antibodies directed against donor-specific HLA molecules, blood group antigen (ABO)-isoagglutinins, or endothelial cell antigens. Antibody-mediated rejection can be a recalcitrant process, resistant to therapy and carries an ominous prognosis to the graft. In concordance with these views, treatment protocols for AMR use permutations of a multiple-prong approach that include (1) the suppression of the T-cell dependent antibody response, (2) the removal of donor reactive antibody, (3) the blockade of the residual alloantibody, and (4) the depletion of naive and memory B-cells. Although all published protocols report a variable rate of success, a major weakness of all current protocols is the lack of effective anti-plasma cell agents. In comparison to acute AMR, the treatment for chronic AMR (CAMR) is not well characterized. Although in acute AMR large titers of pre-existent alloantibodies result in massive activation of the complement system and lytic injury of the graft endothelium, thereby requiring aggressive and fast removal of the offending agents, in CAMR, complement activation results in sublytic endothelial cell injury and activation. Although this type of injury results in chronic graft failure, its slow progression likely renders it amenable of suppression by heightening of maintenance immunosuppression and anti-idiotypic blockade of the circulating alloantibody without the need of plasma exchange. In this review, we will discuss the rationale behind the design of treatment protocols for acute AMR and CAMR as well as their reported results and complications.

A randomized, prospective trial of rituximab for acute rejection in pediatric renal transplantation

We report 1-year outcomes of a randomized study of Rituximab versus standard-of-care immunosuppression (Thymoglobulin and/or pulse steroids) for treatment of biopsy confirmed, acute transplant rejection with B-cell infiltrates, in 20 consecutive recipients (2-23 years). Graft biopsies, with Banff and CADI scores, CD20 and C4d stains, were performed at rejection and 1 and 6 months later. Peripheral blood CMV, EBV and BK viral loads, graft function, DSA, immunoglobulins, serum humanized antichimeric antibody (HACA) and Rituximab, and lymphocyte counts were monitored until 1 year posttreatment. Rituximab infusions were given with a high index of safety without HACA development and increased infections complications. Rituximab therapy resulted in complete tissue B-cell depletion and rapid peripheral B-cell depletion. Peripheral CD19 cells recovered at a mean time of approximately 12 months. There were some benefits for the recovery of graft function (p = 0.026) and improvement of biopsy rejection scores at both the 1- (p = 0.0003) and 6-month (p < 0.0001) follow-up biopsies. Reappearance of C4d deposition was not seen on follow-up biopsies after Rituximab therapy, but was seen in 30% of control patients. There was no change in DSA in either group, independent of rejection resolution. This study reports safety and suggests further investigation of Rituximab as an adjunctive treatment for B-cell-mediated graft rejection.

"To B or not to B?" B-cells and graft rejection

There is increasing evidence that various maturational stages of B-cells infiltrate various solid organ transplants undergoing acute rejection. The presence of immature CD20 and mature CD138 plasma cells associate with more aggressive and steroid-recalcitrant graft rejection and portend poor graft outcomes. Though associative, the causal role of B-cells in graft rejection remains to be better understood. This review discusses the possible roles of B-cells in graft rejection, whether involved as antigen presenting, as indirect effector, or antibody producing cells.

The first year post-heart transplantation: use of immunosuppressive drugs and early complications

A large number of heart transplants are performed annually in different transplant centers in the United States. This is partly because of the improved survival of patients who undergo cardiac transplantation, thus making it a more viable option in the management of end-stage heart failure. The survival benefit after heart transplantation is a result of newer immunosuppressive drug regimens and a better understanding of their effects and interactions. Several studies, mostly involving a small number of patients, describe use and comparison of the many distinct immunosuppressive drugs available to date. Interestingly, many transplant centers perform in-house typical induction treatment regimens because of their own experience and intra-institutional preference. This review summarizes current practices of immunosuppressive drug therapy in the first year post-heart transplant based on the available clinical evidence and discusses future options of heart transplant immunosuppressive drug therapies.

Successful Management of Antibody-Mediated Cardiac Allograft Rejection With Combined Immunoadsorption and Anti-CD20 Monoclonal Antibody Treatment: Case Report and Literature Review

Chronic rejection is still the major limitation of long-term outcome of heart transplant recipients. Several recent studies demonstrated that a not negligible proportion of chronic allograft rejection episodes are not only mediated by T-cell response but also triggered by pre-transplant and de novo post-transplant donor-specific alloantibodies. This points at a fundamental role of humoral immune response mechanisms that contribute to early and late graft failure. This type of rejection is an unsolved problem solid organ transplantation because current immunosuppressive regimens are generally intended to interfere in T-cell signalling pathways. Various options for the removal of circulating alloantibodies and the prevention of alloantibody formation by B-cell depletion have been described. Nevertheless, effective standardized schemes for the treatment of antibody-mediated graft rejection have to be defined. We present a heart transplant recipient with sustained antibody-mediated graft rejection who was successfully managed with a combination treatment consisting of 3 cycles of immunoadsorption and a single-dose administration of the anti-CD20 monoclonal antibody rituximab.

The emerging role of rituximab in organ transplantation

Long-term acceptance of solid organ allografts remains a challenge. While many acute rejection episodes can be treated, new mechanisms of allograft damage are now being defined especially in kidney transplantation. Unexpected clusters of CD20(+) cells have been discovered in renal biopsies performed for clinical rejection. C4d deposition is now routinely seen in refractory rejection. Despite the rapid introduction of new immunosuppressive agents in transplantation, the search for an efficacious anti-B-cell agent remains. With novel mechanisms of allograft damage now being defined, it is important to consider how an anti-B-cell agent might fit into an immunosuppressive regimen. Rituximab is a high-affinity CD20 specific antibody that depletes the B-cell compartment by inducing cellular apoptosis. Thus, it is a rational choice for therapy in transplantation to abrogate B-cell mediated events. In this review, we will discuss the mechanisms of action of rituximab, and its use in for a variety of indications in solid organ transplantation. There are emerging case reports that show that rituximab may be an effective agent to treat antibody-mediated rejection, and post-transplant lymphoproliferative disorder. Rituximab has been frequently cited as an important adjunct therapy in desensitization protocols for highly sensitized transplant recipients as well as recipients of ABO incompatible transplants. Rituximab demonstrates promise in this regard and warrants additional consideration in prospective clinical trials.