Induction immunosuppression with thymoglobulin and rituximab in intestinal and multivisceral transplantation

Updates in induction immunosuppression regimens for intestinal transplantation

Intestinal allografts are the most immunologically complex and carry the highest risk of rejection among solid organ transplantation, necessitating complex immunosuppressive management. We evaluated the latest information regarding induction immunosuppression, with an emphasis on established, novel, and emergent therapies. We also reviewed classic and novel induction immunosuppression strategies for highly sensitized recipients. Comparable progress has been made in intestinal transplantation clinical outcomes since the implementation of induction strategies. This review shows a clear diversity of induction protocols can be observed across different centers. The field of intestinal transplantation is still in its early stages, which is further complicated by the limited number of institutions capable of intestinal transplantation and their geographical variation, which further hinders the development of adequately powered studies in comparison to other organs. As the implementation of institution-specific induction protocols becomes more refined and results are disseminated, future research efforts should be directed towards the development of efficacious induction strategies.

History of clinical intestinal transplantation

The intestines have been considered the "forbidden organ" for years, and intestinal failure became the last organ failure recognized as such in the medical field. The impossibility of providing adequate nutritional support, turned these patients into recipients of just palliative comfort. In the 1960's, parenteral nutrition appeared as the most reasonable replacement therapy, but the initial success obtained with clinical kidney, heart, liver, lung and pancreas transplantation served as background to explore intestinal transplantation. The first clinical report of an isolated intestinal transplant was done by Richard Lillihei in 1967; in 1983, Thomas Starzl, performed the first multi visceral transplant, and in 1990, David Grant performed the first combined liver-intestinal transplant in an adult recipient in Canada. Since then, advances in immunosuppressive therapies and surgical innovations have allowed not only a continuous increase in indications, but also a worldwide application of all procedures, bringing clinical intestinal transplantation to reality. In this historical account, the most important contributions have been summarized, thus describing the steady progress, expansion and novelties developed over the last 56 years, since the first attempt. Clinical intestinal transplantation remains a complex and evolving field; ongoing research and technological advancements will continue shaping its future.

Screening and Management of PTLD

Posttransplant lymphoproliferative disorder (PTLD) represents a heterogeneous group of lymphoproliferative diseases occurring in the setting of immunosuppression following hematopoietic stem cells transplant and solid organ transplantation. Despite its overall low incidence, PTLD is a serious complication following transplantation, with a mortality rate as high as 50% in transplant recipients. Therefore, it is important to establish for each transplant recipient a personalized risk evaluation for the development of PTLD based on the determination of Epstein-Barr virus serostatus and viral load following the initiation of immunosuppression. Due to the dynamic progression of PTLD, reflected in the diverse pathological features, different therapeutic approaches have been used to treat this disorder. Moreover, new therapeutic strategies based on the administration of virus-specific cytotoxic T cells have been developed. In this review, we summarize the available data on screening and treatment to suggest a strategy to identify transplant recipients at a higher risk for PTLD development and to review the current therapeutic options for PTLD.

Liver Inclusion Appears to Be Protective Against Graft Loss-Due-to Chronic But Not Acute Rejection Following Intestinal Transplantation

In intestinal transplantation, while other centers have shown that liver-including allografts have significantly more favorable graft survival and graft loss-due-to chronic rejection (CHR) rates, our center has consistently shown that modified multivisceral (MMV) and full multivisceral (MV) allografts have significantly more favorable acute cellular rejection (ACR) and severe ACR rates compared with isolated intestine (I) and liver-intestine (LI) allografts. In the attempt to resolve this apparent discrepancy, we performed stepwise Cox multivariable analyses of the hazard rates of developing graft loss-due-to acute rejection (AR) vs. CHR among 350 consecutive intestinal transplants at our center with long-term follow-up (median: 13.5 years post-transplant). Observed percentages developing graft loss-due-to AR and CHR were 14.3% (50/350) and 6.6% (23/350), respectively. Only one baseline variable was selected into the Cox model indicating a significantly lower hazard rate of developing graft loss-due-to AR: Transplant Type MMV or MV (p < 0.000001). Conversely, two baseline variables were selected into the Cox model indicating a significantly lower hazard rate of developing graft loss-due-to CHR: Received Donor Liver (LI or MV) (p = 0.002) and Received Induction (p = 0.007). In summary, while MMV/MV transplants (who receive extensive native lymphoid tissue removal) offered protection against graft loss-due-to AR, liver-containing grafts appeared to offer protection against graft loss-due-to CHR, supporting the results of other studies.

Small bowel transplant - novel indications and recent progress

INTRODUCTION

Advances in the management of intestinal failure have led to a reduction in the number of intestinal transplants. The number of bowel transplants has been mainly stable even though a slight increase has been observed in the last 5 years.

AREAS COVERED

Standard indication includes patients with a reasonable life expectancy. Recent progress can be deduced by the increased number of intestine transplants in adults: this is due to the continuous improvement of 1-year graft survival worldwide (without differences in 3- and 5-year) associated with better abdominal wall closure techniques. This review aims to provide an update on new indications and changes in trends of pediatric and adult intestine transplantation. This analysis, which stretches through the past 5 years, is based on a collection of related manuscripts from PubMed.

EXPERT COMMENTARY

Intestinal transplants should be solely intended for a group of individuals for whom indications for transplantation are clear and both medical and surgical rehabilitations have failed. Nevertheless, many protocols developed over the years have not yet solved the key question represented by the over-immunosuppression. Novel indications and recent progress in the bowel transplant field, minimal yet consistent, represent a pathway to be followed.

Induction Versus Maintenance Immunosuppression After Intestinal Transplant: Determining Which Treatment Most Impacts Long-Term Patient And Graft Survival

OBJECTIVES

Immunosuppressive strategies for intestinal transplant have changed over time. However, specific intestinal transplant-oriented protocols and reports on long-term maintenance regimens are scarce. Our objective was to evaluate the impact of 2 different initial immunosuppressive protocols based on thymoglobulin (group A) and basiliximab (anti-interleukin 2 antibody) (group B) and of changes to maintenance immunosuppression over long-term follow-up in intestinal transplant recipients.

MATERIALS AND METHODS

We performed a retrospective analysis of a prospectively established protocol for intestinal transplant immunosuppression, conducted between May 2006 and December 2020. We analyzed 51 intestinal transplant recipients, with 6 patients excluded because of early death or graft loss. Acute cellular rejection frequency and grade, number of acute cellular rejection episodes, time to the first acute cellular rejection episode, response to treatment, number of patients who progressed to chronic allograft rejection, kidney function, infections, incidence of posttransplant lymphoproliferative disorder and graft-versus-host disease, and patient and graft survival were analyzed.

RESULTS

In the study groups, there were 87 acute cellular rejection episodes in 45 patients (33 in group A and 54 in group B). We found degree of acute cellular rejection to be mild in 45 patients, moderate in 18, and severe in 24 (not significant between groups). Our comparison of induction therapy (thymoglobulin [group A] vs interleukin 2 antibody [group B]) did not show any statistical difference during clinical followup. Long-term review showed that all patients were on tacrolimus. Five-year patient and graft survival rates were 62% and 45% for group A and 54% and 46% for group B, respectively (not significant).

CONCLUSIONS

Long-term patient and graft outcomes reflected the use of an individualized follow-up with adjustments and changes in immunosuppressive medications according to the patient's clinical course and complications rather than based on the induction immunosuppressive protocol used.

Update on immunosuppressive strategies in intestinal transplantation

PURPOSE OF REVIEW

The intestine is the most immunologically complex solid organ allograft with the greatest risk of both rejection and graft-versus-host disease (GVHD). High levels of immunosuppression are required, further increasing morbidity. Due to low volume of transplants and few centers with experience, there is paucity of evidence-based, standardized, and effective therapeutic regimens. We herein review the most recent data about immunosuppression, focusing on novel and emerging therapies.

RECENT FINDINGS

Recent data are moving the field toward increasing use of basilixumab and consideration of alemtuzumab for induction and inclusion of mammalian target of rapamycin inhibitors and antimetabolites for maintenance. For rejection, we highlight novel roles for tumor necrosis factor-α inhibition, α4β7 integrin inhibition, microbiome modulation, desensitization protocols, and tolerance induction strategies. We also highlight emerging novel therapies for GVHD, especially the promising role of Janus kinase inhibition.

SUMMARY

New insights into immune pathways associated with rejection and GVHD in intestinal allografts have led to an evolution of therapies from broad-based immunosuppression to more targeted strategies that hold promise for reducing morbidity from infection, rejection, and GVHD. These should be the focus of further study to facilitate their widespread use.

Immunosuppression in liver and intestinal transplantation

Immunosuppression handling plays a key role in the early and long-term results of transplantation. The development of multiple immunosuppressive drugs led to numerous clincial trials searching to reach the ideal regimen. Due to heterogeneity of the studied patient cohorts and flaws in many, even randomized controlled, study designs, the answer still stands out. Nowadays triple-drug immunosuppression containing a calcineurin inhibitor (preferentially tacrolimus), an antimetabolite (using mycophenolate moffettil or Azathioprine) and short-term steroids with or without induction therapy (using anti-IL2 receptor blocker or anti-lymphocytic serum) is the preferred option in both liver and intestinal transplantation. This chapter aims, based on a critical review of the definitions of rejection, corticoresistant rejection and standard immunosuppression to give some reflections on how to reach an optimal immunosuppressive status and to conduct trials allowing to draw solid conclusions. Endpoints of future trials should not anymore focus on biopsy proven, acute and chronic, rejection but also on graft and patient survival. Correlation between early- and long-term biologic, immunologic and histopathologic findings will be fundamental to reach in much more patients the status of operational tolerance.

Low incidence of posttransplant lymphoproliferative disorder after allogeneic stem cell transplantation in patients with lymphoma treated with rituximab

Posttransplant lymphoproliferative disorder (PTLD) is a serious complication after hematopoietic stem cell transplantation (HSCT). Several studies of risk factors for PTLD have been reported; however, the probability of, and risk factors for, PTLD in patients with lymphoma is unknown. Japanese nationwide transplant registry data from 5270 patients with lymphoma after allogeneic HSCT were analyzed. Mature B-cell, T/NK-cell, and T-cell lymphoblastic subtypes accounted for 49%, 26%, and 9.6% of lymphoma cases, respectively. Rituximab was used in 1678 lymphoma patients, most of whom (89%) received HSCT for mature B-cell lymphoma. Thirty-one patients with lymphoma developed PTLD, representing a probability of 0.77% at 2 years post-HSCT, which did not differ significantly from that in patients with other diseases (P = .98). Year of HSCT after 2010 (hazard ratio [HR] = 5.6, 95% confidence interval [CI], 1.48-21.3), antithymocyte globulin (ATG) use in the conditioning regimen (HR = 4.5, 95% CI, 1.61-12.5), and no rituximab use before HSCT (HR = 3.2, 95% CI, 1.26-7.90) were identified as risk factors for PTLD. Probabilities of PTLD at 1 year post-HSCT according to rituximab and ATG use were 0.23% (rituximab+, ATG-), 0.75% (rituximab-, ATG-), 1.25% (rituximab+, ATG+), and 3.53% (rituximab-, ATG+). Regarding lymphoma subtypes, patients with mature B-cell lymphoma had the lowest incidence of PTLD (0.35% at 2 years). Among high-risk patients receiving ATG, the mortality rate due to infection was elevated in those previously treated with rituximab (22%) relative to those without (14%); however, the difference was not significant (P = .10). Rituximab use before HSCT significantly reduces the risk of PTLD. Adding rituximab to the conditioning regimen is potentially a good strategy to prevent the development of PTLD in high-risk patients.

Association of More Intensive Induction With Less Acute Rejection Following Intestinal Transplantation: Results of 445 Consecutive Cases From a Single Center

BACKGROUND

In intestinal transplantation, acute cellular rejection (ACR) remains a significant challenge to achieving long-term graft survival. It is still not clear which are the most important prognostic factors.

METHODS

We performed a Cox multivariable analysis of the hazard rates of developing any ACR, severe ACR, and cause-specific graft loss during the first 60 months posttransplant among 445 consecutive intestinal transplant recipients at our institution since 1994. Of particular interest was to determine the prognostic influence of induction type: rabbit antithymocyte globulin (rATG; 2 mg/kg × 5)/rituximab (150 mg/m × 1; begun in 2013), alemtuzumab (2001-2011), and less intensive forms.

RESULTS

First ACR and severe ACR occurred in 61.3% (273/445) and 22.2% (99/445) of cases. The following 3 multivariable predictors were associated with significantly lower hazard rates of developing ACR and severe ACR: transplant type modified multivisceral or full multivisceral (P = 0.0009 and P < 0.000001), rATG/rituximab induction (P < 0.000001 and P < 0.01), and alemtuzumab induction (P = 0.004 and P = 0.07). For both ACR and severe ACR, the protective effects of rATG/rituximab and alemtuzumab were highly significant (P ≤ 0.000005 for ACR; P ≤ 0.01 for severe ACR) but only during the first 24 days posttransplant (when the ACR hazard rate was at its peak). The prognostic effects of rATG/rituximab and alemtuzumab on ACR/severe ACR disappeared beyond 24 days posttransplant (ie, nonproportional hazards). While significant protective effects of both rATG/rituximab and alemtuzumab existed during the first 6 months posttransplant for the hazard rate of graft loss-due-to-rejection (P = 0.01 and P = 0.003), rATG/rituximab was additionally associated with a consistently lower hazard rate of graft loss-due-to-infection (P = 0.003). All significant effects remained after controlling for the propensity-to-be-transplanted since 2013.

CONCLUSIONS

More intensive induction was associated with a significant lowering of ACR risk, particularly during the early posttransplant period.

One-year Incidence of Infection in Pediatric Intestine Transplantation

BACKGROUND

This study reports the infection rate, location of infection and pathogen causing bacterial, fungal or viral infections in intestine transplant recipients at a pediatric transplant center.

METHODS

Records from a pediatric center were reviewed for patients receiving an intestine transplant. Positive cultures and pathology reports were used to diagnose bacterial, fungal and viral infections and also to determine location and infectious agent. Risk for infection was assessed based on liver or colon inclusion, and immunosuppression induction, as part of the intestine transplant.

RESULTS

During the study period, 52 intestine transplants were performed on 46 patients. Bacterial, fungal and viral infection rates were 90%, 25% and 75%, respectively. Enterococcus spp. (non-vancomycin-resistant enterococci) were the most common pathogens and were isolated from 52% of patients. Non-vancomycin-resistant enterococci was present in 12% of transplant recipients. Candida spp. were the most common fungal pathogens (23% of patients). Respiratory viral infections were common (44%), and Cytomegalovirus infection rate was 17%. Common sites of infection were bloodstream, urinary and upper respiratory tract. Colon and liver inclusion in the transplant graft was not associated with increased risk of infection, nor was addition of rituximab to the immunosuppression induction protocol.

CONCLUSIONS

Postintestine transplant infections are ubiquitous in the pediatric population, including high rates of infection from bacterial, viral and fungal sources. Inclusion of the liver and/or colon as a component of the transplant graft did not appear to greatly impact the infectious risk. Adding rituximab to the immunosuppression induction protocol did not impact on infectious risk.

Post-intestine transplant graft-vs-host disease associated with inclusion of a liver graft and with a high mortality risk

INTRODUCTION

This study reports the incidence, anatomic location, and outcomes of graft-vs-host disease (GVHD) at a single active intestine transplant center.

METHODS

Records were reviewed for all patients receiving an intestine transplant from 2003 to 2015. Pathology reports and pharmacy records were reviewed to establish the diagnosis, location, and therapeutic interventions for GVHD.

RESULTS

A total of 236 intestine transplants were performed during the study period, with 37 patients (16%) developing GVHD. The median time to onset of disease was 83 days, with 89% of affected patients diagnosed in the first year post-transplant. Mortality for affected patients was 54% in the 1 year after GVHD diagnosis. Skin lesions were the most common manifestation of GVHD. Other sites of disease included lungs, bone marrow, oral mucosa, large intestine, and brain. The incidence of GVHD was 16% in adult patients, and slightly lower in pediatric recipients (13%). In adults, increasing graft volume (isolated vs multi-organ) and liver inclusion were associated with increasing risk of GVHD, though this was not seen in pediatric patients.

CONCLUSION

Overall, 16% of intestine transplant recipients developed GVHD. GVHD is associated with high mortality, and disease in the lungs, brain, and bone marrow was universally fatal.

Improvements in intestine transplantation

Transplantation of the intestine in children has presented significant challenges even as it has become a standard to treat nutritional failure due to short gut syndrome. These challenges have been addressed in part by significant improvements in short and long-term care. Noteworthy enhancements include reduced need for intestine transplantation, drug-sparing immunosuppressive regimens, immune monitoring, and improved surveillance and management of PTLD and non-adherence.

Complications in pediatric intestine transplantation in the absence of peri-operative donor or recipient bowel decontamination

This study reports the clinical complication and infection rates of an active pediatric IT program that has never utilized bowel decontamination in either the donor or the recipient. All patients undergoing IT from 2003 to 2015 at a single pediatric IT center were reviewed. Post-transplant surgical, infectious, and immunosuppressive complications are reported. There were 52 patients who underwent IT during the study period. Among these patients, 4% developed a postoperative abscess, one developed an enteric fistula (2%), and one had an enteric or anastomotic leak (2%). The rate of any bacterial infection was 90% in the first year, with a wound infection rate of 23%. Any fungal infection occurred in 25% of patients. Any viral infection occurred in 75% of patients. Gastrointestinal viruses were diagnosed in 52% of patients, and cytomegalovirus infections occurred in 17%. Rejection rates were 39% at any time post-transplant (isolated 44% and 35% for multivisceral patients). At this center in which no bowel decontamination was used, rates of surgical complications, infections, and rejection were similar to those reported by other centers. These findings suggest bowel decontamination may provide no significant benefit in this population of high-risk transplant patients.

Challenges with Intestine and Multivisceral Re-Transplantation: Importance of Timing of Re-Transplantation and Optimal Immunosuppression

BACKGROUND Patients undergoing re-transplantation often receive high doses of immunosuppression, which may lead to an immunocompromised status of the recipient. This study investigates the outcomes after intestine/multivisceral re-transplantation. MATERIAL AND METHODS Clinical outcomes of 23 patients undergoing 24 re-transplantations at a single intestine transplant center were reviewed. Bone marrow suppression was used as a surrogate marker of immunocompromised status, and was defined as platelet count <50 k/mm3 and absolute lymphocyte count <200/mm³. RESULTS All re-transplants except one were liver inclusive. Fifteen of 23 patients died at a median time of 12 months (range 0.2-75) after re-transplantation. Of the 15 deaths, nine (60%) resulted from complications associated with a compromised host immune status: graft versus host disease (GVHD) affecting bone marrow (three cases), persistent viral infection (three cases), post-transplant lymphoproliferative disorder (PTLD (one case), metastatic cancer (one case), multi-drug resistant polymicrobial sepsis (one case). Four deaths (27%) resulted from severe rejection. Non-survivors were more likely to have received alemtuzumab, and had higher incidence of bone marrow suppression. In addition to immunocompromised status and rejection, the use of alemtuzumab was associated with mortality after intestinal/multivisceral re-transplantation. CONCLUSIONS High mortality was associated with intestine/multivisceral re-transplantation. To improve clinical outcomes of intestine and multivisceral transplantation, it is important to allow reconstitution of host immunity. Longer interval between the two transplantations, and strategies such as allograft specific immunosuppression, may spare the host from the devastating effects of potent immunosuppression currently used.

Multivisceral transplant is a viable treatment option for patients with non-resectable intra-abdominal fibromatosis

BACKGROUND

Intra-abdominal fibromatosis often involves the mesentery root which is non-resectable by conventional surgery. Multivisceral transplant (MVT), as a potential cure to non-resectable fibromatosis, has rarely been reported and the prognosis is unknown.

METHODS

Six patients who underwent MVT for intra-abdominal fibromatosis were reviewed. Clinicopathological features, immunohistochemistry for β-catenin, p53, and Ki67, and outcomes were evaluated. Appropriate data for comparative analysis were obtained from a cohort of 24 patients who underwent conventional resection for intra-abdominal fibromatosis.

RESULTS

Among six MVT patients, four had familial adenomatous polyposis (FAP). Two patients had an initial intestinal transplantation, three had multiple prior surgeries, and two had adjuvant therapy. One patient died of hemorrhagic stroke shortly after MVT, and five patients (83%) survived with a median follow-up of 64 months. The 1-year and 5-year survival rates were 67% for all five patients. Two patients had recurrences after MVT and one of them had FAP. In comparison, six of 24 patients who underwent conventional surgery had FAP; six (25%) had recurrences and three had FAP. For FAP patients; the mean recurrence time was 13 months for MVT versus 6 months for conventional surgery. Ki67 proliferative index, β-catenin, and p53 expression did not significantly correlate to recurrence.

CONCLUSIONS

Multivisceral transplant (MVT) is a viable option for patients who have non-resectable intra-abdominal fibromatosis with promising surviving rates, although recurrence still occurs. Surgical margin, Ki67 proliferative index, β-catenin, and p53 expression are not predicative for recurrence of fibromatosis.

The role of biologicals in intestinal transplantation

PURPOSE OF REVIEW

This article reviews the role of biologicals in intestinal transplantation.

RECENT FINDINGS

Several biologicals have been used in intestinal and multivisceral transplantation for various indications, such as induction therapy, prevention and treatment of antibody-mediated rejection, desensitization, anti-inflammatory treatment, as well as treatment of Epstein-Barr virus-associated posttransplant lymphoproliferative disease. Particularly, the administration of biologicals in induction therapy such as T-cell depleting antibodies and interleukin-2 receptor antagonists have significantly contributed to the great improvement of patient and allograft outcome. Novel biologicals, such as B-cell, plasma-cell, and complement-directed agents have been successfully applied to treat antibody and complement-driven alloimmune processes to stabilize long-term outcome. Several other inflammatory allotransplant conditions have been addressed with anti-TNF-α antibodies, such as infliximab.

SUMMARY

Biologicals have contributed significantly to the recent success of intestinal transplantation. Novel developments in this field are supposed to aid in addressing various urgent needs in intestinal transplantation, such as preimmunization, antibody and complement-induced graft injury, as well as pathologies originating from innate immune responses.

Cytomegalovirus Infection After Intestinal/Multivisceral Transplantation: A Single-Center Experience With 210 Cases

BACKGROUND

Cytomegalovirus (CMV) infection is the most prevalent infectious complication after solid organ transplantation, and recipients of isolated intestinal transplantation (IIT)/multivisceral transplantation (MVT) are among those at the highest risk. Limited clinical data exist regarding CMV infection after IIT/MVT. The aim of this study is to analyze risk factors for posttransplant CMV infection and to assess the efficacy and validity of our prophylaxis and treatment regimens in intestinal transplantation.

METHODS

Medical records of 210 IIT/MVT patients were retrospectively reviewed. Posttransplant CMV prophylaxis regimen consisted of ganciclovir followed by 1 year of valganciclovir. The addition of CMV immunoglobulin (CMVIG) was decided according to donor/recipient CMV serostatus (D/R). All results of CMV PCR and/or pp65 antigenemia, and pathological reports were reviewed. Time to the incidence of CMV infection (viremia and/or tissue invasive disease) and risk factors for CMV infection were investigated.

RESULTS

CMV infection was observed in 34 of 210 (16%) with a median onset of 347 days. Rejection was significantly associated with CMV infection (P = 0.01, odds ratio = 2.61). In the high-risk serostatus group (D+/R-), prophylactic CMVIG and induction with high-dose rabbit antithymocyte globulin (>10 mg/kg) were associated with a lower CMV infection rate on univariate analysis. The CMVIG remained to be an independent factor on multivariate analysis (P = 0.04, hazard ratio = 0.93/dose). Mortality associated with CMV infection occurred in 4, and CMV infection adversely affected patient survival (P = 0.001, hazard ratio = 2.71).

CONCLUSIONS

Prophylaxis with CMVIG and appropriate induction with rabbit antithymocyte globulin may be important to reduce CMV infection in high-risk serostatus group (D+/R-).

The Influence of Immunosuppressive Agents on the Risk of De Novo Donor-Specific HLA Antibody Production in Solid Organ Transplant Recipients

Production of de novo donor-specific antibodies (dnDSA) is a major risk factor for acute and chronic antibody-mediated rejection and graft loss after all solid organ transplantation. In this article, we review the data available on the risk of individual immunosuppressive agents and their ability to prevent dnDSA production. Induction therapy with rabbit antithymocyte globulin may achieve a short-term decrease in dnDSA production in moderately sensitized patients. Rituximab induction may be beneficial in sensitized patients, and in abrogating rebound antibody response in patients undergoing desensitization or treatment for antibody-mediated rejection. Use of bortezomib for induction therapy in at-risk patients is of interest, but the benefits are unproven. In maintenance regimens, nonadherent and previously sensitized patients are not suitable for aggressive weaning protocols, particularly early calcineurin inhibitor withdrawal without lymphocyte-depleting induction. Early conversion to mammalian target of rapamycin inhibitor monotherapy has been reported to increase the risk of dnDSA formation, but a combination of mammalian target of rapamycin inhibitor and reduced-exposure calcineurin inhibitor does not appear to alter the risk. Early steroid therapy withdrawal in standard-risk patients after induction has no known dnDSA penalty. The available data do not demonstrate a consistent effect of mycophenolic acid on dnDSA production. Risk minimization for dnDSA requires monitoring of adherence, appropriate risk stratification, risk-based immunosuppression intensity, and prospective DSA surveillance.

Post-transplant lymphoproliferative disorders

Post-transplant lymphoproliferative disorders (PTLDs) are a group of conditions that involve uncontrolled proliferation of lymphoid cells as a consequence of extrinsic immunosuppression after organ or haematopoietic stem cell transplant. PTLDs show some similarities to classic lymphomas in the non-immunosuppressed general population. The oncogenic Epstein-Barr virus (EBV) is a key pathogenic driver in many early-onset cases, through multiple mechanisms. The incidence of PTLD varies with the type of transplant; a clear distinction should therefore be made between the conditions after solid organ transplant and after haematopoietic stem cell transplant. Recipient EBV seronegativity and the intensity of immunosuppression are among key risk factors. Symptoms and signs depend on the localization of the lymphoid masses. Diagnosis requires histopathology, although imaging techniques can provide additional supportive evidence. Pre-emptive intervention based on monitoring EBV levels in blood has emerged as the preferred strategy for PTLD prevention. Treatment of established disease includes reduction of immunosuppression and/or administration of rituximab (a B cell-specific antibody against CD20), chemotherapy and EBV-specific cytotoxic T cells. Despite these strategies, the mortality and morbidity remains considerable. Patient outcome is influenced by the severity of presentation, treatment-related complications and risk of allograft loss. New innovative treatment options hold promise for changing the outlook in the future.

Prospective Monitoring of Donor-specific Anti-HLA Antibodies After Intestine/Multivisceral Transplantation: Significance of De Novo Antibodies

BACKGROUND

Presence of circulating donor-specific antibodies (DSA) may be associated with worse clinical outcomes after intestine/multivisceral transplantation.

METHODS

In 79 intestine/multivisceral recipients, sera were prospectively screened for DSA by Luminex Single antigen test at 1, 3, 6, 9, 12, 18, 24, and 36 months after transplantation. Standard immunosuppression included thymoglobulin-rituximab induction and tacrolimus-prednisone maintenance. C4d staining was performed retrospectively on biopsies in patients that developed acute rejection (AR).

RESULTS

Twenty-two (28%) patients developed de novo DSA at a median posttransplant period of 3 (1-36) months. De novo DSA were observed in 10 of 40 liver-including and 12 of 39 liver-excluding transplants (P = 0.57). Occurrence of AR was slightly higher in patients with de novo DSA (45% vs 33%, respectively; P = 0.41). Similarly, chronic rejection (14% vs 5%; P = 0.21) and graft loss due to AR (18% vs 7%; P = 0.14) were numerically higher in patients with de novo DSA. Only 35% patients experiencing AR had circulating de novo DSA at the time of AR. Antibody-mediated rejection was diagnosed in 6 patients based on C4d staining, of these 2 patients had circulating de novo DSA at the time of biopsy.

CONCLUSIONS

De novo DSA formation, particularly early in the posttransplant course may be associated with trends toward worse outcomes. However, its significance in the pathophysiology of AR remains uncertain. Studies focusing mechanisms of DSA-related graft injury and intragraft DSA detection might provide further insight into this issue.

Eculizumab Salvage Therapy for Antibody-Mediated Rejection in a Desensitization-Resistant Intestinal Re-Transplant Patient

The presence of elevated calculated panel reactive antibody (cPRA) and anti-HLA donor specific antibodies (DSA) are high risk factors for acute antibody-mediated rejection (AAMR) in intestinal transplantation that may lead to graft loss. Eculizumab has been used for the treatment of AAMR in kidney transplantation of sensitized patients that do not respond to other treatment. Here, we report a case where eculizumab was used to treat AAMR in a desensitization-resistant intestinal re-transplant patient. A male patient lost his intestinal graft to AAMR 8.14 years after his primary transplant. He received a second intestinal graft that had to be explanted a month later due to refractory AAMR. The patient remained highly sensitized despite multiple treatments. He received a multivisceral graft and presented with severe AAMR on day 3 posttransplantation. The AAMR was successfully treated with eculizumab. The patient presently maintains an elevated cPRA level above 90% but his DSAs have decreased from 18 000 MFI (mean fluorescent intensity) to below the positive cut-off value of 3000 MFI and remains rejection free with a 2-year follow-up since his multivisceral transplant. Eculizumab offers an alternative to treat AAMR in intestinal transplantation in desensitization-resistant patients.

New directions for rabbit antithymocyte globulin (Thymoglobulin(®)) in solid organ transplants, stem cell transplants and autoimmunity

In the 30 years since the rabbit antithymocyte globulin (rATG) Thymoglobulin^® was first licensed, its use in solid organ transplantation and hematology has expanded progressively. Although the evidence base is incomplete, specific roles for rATG in organ transplant recipients using contemporary dosing strategies are now relatively well-identified. The addition of rATG induction to a standard triple or dual regimen reduces acute cellular rejection, and possibly humoral rejection. It is an appropriate first choice in patients with moderate or high immunological risk, and may be used in low-risk patients receiving a calcineurin inhibitor (CNI)-sparing regimen from time of transplant, or if early steroid withdrawal is planned. Kidney transplant patients at risk of delayed graft function may also benefit from the use of rATG to facilitate delayed CNI introduction. In hematopoietic stem cell transplantation, rATG has become an important component of conventional myeloablative conditioning regimens, following demonstration of reduced acute and chronic graft-versus-host disease. More recently, a role for rATG has also been established in reduced-intensity conditioning regimens. In autoimmunity, rATG contributes to the treatment of severe aplastic anemia, and has been incorporated in autograft projects for the management of conditions such as multiple sclerosis, Crohn’s disease, and systemic sclerosis. Finally, research is underway for the induction of tolerance exploiting the ability of rATG to induce immunosuppresive cells such as regulatory T-cells. Despite its long history, rATG remains a key component of the immunosuppressive armamentarium, and its complex immunological properties indicate that its use will expand to a wider range of disease conditions in the future.

The current state of intestine transplantation: indications, techniques, outcomes and challenges

Intestine transplantation is the least common form of organ transplantation in the United States and often deemed one of the most difficult. Patient and graft survival have historically trailed well behind other organ transplants. Over the past 5-10 years registry reports and single center series have demonstrated improvements to patient survival after intestinal transplantation that now match patient survival for those without life-threatening complications on parenteral nutrition. For various reasons including improvements in medical care of patients with intestinal failure and difficulty accessing transplant care, the actual number of intestine transplants has declined by 25% over the past 6 years. In light of the small numbers of intestine transplants, many physicians and the lay public are often unaware that this is a therapeutic option. The aim of this review is to describe the current indications, outcomes and advances in the field of intestine transplantation and to explore concerns over future access to this important and life-saving therapy.

Crossmatch-positive liver transplantation in patients receiving thymoglobulin-rituximab induction

BACKGROUND

Positive crossmatch (CM) in liver transplantation (LT) is associated with worse outcomes. Role of induction immunosuppression in this setting remains to be studied.

METHODS

One thousand consecutive LT patients receiving rabbit antithymocyte globulin±rituximab induction were studied. Pretransplantation sera of 55 CM-positive (CM) patients were tested for C1q-fixing donor-specific antibodies (DSA). Diagnosis of antibody-mediated rejection required presence of diffuse vascular C4d expression on liver biopsies.

RESULTS

CM was positive in 112 (11%) recipients. Antibody-mediated rejection was observed in 3 (0.03%) patients, whereas acute cellular rejection (ACR) occurred in 31 (3%) patients. CM status was associated with a higher incidence of ACR (9% in CM vs. 2% in CM-negative [CM]; P<0.01) and chronic rejection (4% in CM vs. 1% in CM; P<0.01). Graft survival was slightly lower in CM patients (at 1 year; 85% in CM vs. 89% in CM; P=0.26). Patients with autoimmune hepatitis, primary sclerosing cholangitis, and primary biliary cirrhosis as a group had a tendency toward CM status as well as developing ACR. Upon multivariate analysis, CM status was the strongest predictor of ACR (B=1.14; P=0.02). Only half of CM patients harbored C1q-fixing DSA. Presence of C1q-fixing DSA was not associated with increased incidence of ACR.

CONCLUSIONS

In LT, CM status is associated with an increased incidence of acute rejection, chronic rejection, and slightly worse graft survival. With the use of rabbit antithymocyte globulin±rituximab induction, overall low rejection rates can be achieved in CM LT.

Prevention and treatment for Epstein-Barr virus infection and related cancers

Epstein-Barr virus (EBV) was the first herpes virus described as being oncogenic in humans. EBV infection is implicated in post-transplant lymphoproliferative diseases (PTLD) and several other cancers in non-immunocompromised patients, with more than 200,000 new cases per year. While prevention of PTLD is improving, mainly based on EBV monitoring and preemptive tapering of immunosuppression, early diagnosis remains the best current option for the other malignancies. Significant progress has been achieved in treatment, with decreased mortality and morbidity, but some challenges are still to face, especially for the more aggressive diseases. Possible prevention by EBV vaccination would be a more global approach of this public health problem, but further active research is needed before this goal could be reached.

Clinicopathologic features of post-transplant lymphoproliferative disorders arising after pediatric small bowel transplant

Few studies examined the clinicopathologic features of PTLD arising in pediatric SBT patients. Particularly, the association between ATG and PTLD in this population has not been described. Retrospective review of 81 pediatric patient charts with SBT--isolated or in combination with other organs--showed a PTLD incidence of 11%, occurring more frequently in females (median age of four yr) and with clinically advanced disease. Monomorphic PTLD was the most common histological subtype. There was a significant difference in the use of ATG between patients who developed PTLD and those who did not (p < 0.01); a similar difference was seen with the use of sirolimus (p < 0.001). These results suggested a link between the combination of ATG and sirolimus and development of more clinically and histologically advanced PTLD; however, the risk of ATG by itself was not clear. EBV viral loads were higher in patients with PTLD, and median time between detection of EBV to PTLD diagnosis was three months. However, viral loads at the time of PTLD diagnosis were most often lower than at EBV detection, thereby raising questions on the correlation between decreasing viral genomes and risk of PTLD.

Intestinal and multivisceral retransplantation results: literature review

BACKGROUND

Intestinal/multivisceral transplantation (IT/MVT) is the gold standard treatment for patients with intestinal failure and complications related to total parenteral nutrition, gastrointestinal inoperable indolent tumors, or diffuse portal trombosis. Currently, the reported 1-year patient survival rate is around 80%, similar to other solid organ abdominal transplantations. Unfortunately, the patient survival decreases after the first year with the 5-year rate not close to 70% yet. Acute cellular rejection is the main cause of graft loss. Its early diagnosis may make it possible to improve survival of retransplantations.

OBJECTIVE

To analyze the reported results published in the last 5 years by leading transplant centers to evaluate IT/MVT retransplantation results.

METHODS

We performed a literature review using PubMed focusing on multivisceral and intestinal retransplantation in articles published between 2006 and 2012. In relation to the first transplantation, we analyzed demographics, imunosuppression, rejection, infection as well as graft and patient survival rates.

RESULTS

Two centers reported results on intestinal and multivisceral retransplantations. Mazariegos et al reported their experience with 15 intestinal retransplantations in 14 pediatric recipients. Four patients died from posttransplant lymphoperliferative disease, severe acute cellular rejection, fungal sepsis, or bleeding from a pseudoaneurysm at a mean time of 5.7 months post-transplantation. Total parenteral nutrition was weaned at a median time of 32 days. Abu-Elmaged et al reported 47 cases with a 5-year survival of 47% for all retransplant modalities. Retransplantation with liver-contained visceral allograft achieved a 5-year survival rate of 61% compared with 16% for liver-free visceral grafts.

CONCLUSION

Despite those huge improvements, some transplanted patients develop severe acute cellular rejection, culminating in graft loss and retransplantation. Repots on multivisceral and intestinal retransplantation outcomes suggest that it is a viable procedure with appropriate patient survival after primary graft loss.

Impact of pediatric intestinal transplantation on intestinal failure in Japan: findings based on the Japanese intestinal transplant registry

INTRODUCTION

We assessed the impact of intestinal transplantation on Japanese pediatric patients with intestinal failure with data from the Japanese intestinal transplant registry.

METHODS

Standardized forms were sent to all known intestinal transplantation programs, requesting information on transplants performed between 1996 and June 30, 2012. Patients younger than 18 years were analyzed. Patient and graft survival estimates were obtained using the Kaplan-Meier method.

RESULTS

Of the 14 intestinal transplants, 4 were deceased and 10 were living donor transplants. The primary indications were: short gut syndrome (n = 7), intestinal functional disorder (n = 6), and re-transplantation (n = 1). The overall 1- and 5-year patient survival rates were 77 and 57%, respectively. In transplants performed after 2006 (n = 6), the one-year patient survival rate was 83%, and the 5-year survival rate was 83%. Graft one- and 5-year survival rates were 83 and 83%, respectively. The living-related transplant survival rate was 80% at 1 year and 68% at 2 years, compared to 67 and 67% for cadaveric transplant recipients. There were no statistically significant differences in patient (p = 0.88) and graft (p = 0.76) survival rates between living donor and cadaveric transplant recipients. All current survivors discontinued PN.

CONCLUSION

Intestinal transplantation has become an effective therapy for patients with intestinal failure who cannot tolerate PN.

Impact of positive flow cytometry crossmatch on outcomes of intestinal/multivisceral transplantation: role anti-IL-2 receptor antibody

BACKGROUND

Positive crossmatch may be associated with an increased risk of acute rejection (AR) and worse overall outcomes after intestinal/multivisceral (MV) transplantation. However, the evidence from published studies in this setting is sparse and contradictory. This study reports the impact of positive flow cytometry crossmatch on clinical outcomes after intestinal/MV transplantation and the use of anti-interleukin (IL)-2 receptor antibody as a maintenance immunosuppressant.

METHODS

Records of all intestinal/MV transplants from 2003 to 2010 were reviewed. Flow cytometry was used to evaluate T- and B-cell crossmatch status. Standard immunosuppression included rabbit anti-thymocyte globulin-rituximab induction with tacrolimus and steroid maintenance. From 2008 onwards (second era), monthly anti-IL-2 receptor antibody was added to the maintenance immunosuppression in patients receiving liver-excluding transplants.

RESULTS

Of 131 intestinal/MV transplants, 27 (21%) had a positive crossmatch. Positive crossmatch was not associated with an increased incidence of AR and graft loss (30% and 37% vs. 29% and 47%; P=0.94 and 0.35, respectively). This effect was maintained in liver-excluding transplants. Overall rate of AR decreased from 39% to 22% in the second era. In liver-excluding transplants, there was a significant decrease in AR from 75% to 44% with the use of anti-IL-2 receptor antibody therapy.

CONCLUSIONS

With rabbit anti-thymocyte globulin-rituximab induction, positive crossmatch status is not associated with worse outcomes after intestinal/MV transplantation. Use of anti-IL-2 receptor antibody as a part of maintenance immunosuppression may be beneficial in liver-excluding transplants.

Intestinal and multivisceral transplantation immunosuppression protocols--literature review

INTRODUCTION

Currently the most used techniques for small bowel transplant are isolated intestinal transplantation, multivisceral transplantation (MVT), and modified multivisceral transplantation. One important factor is early diagnosis of acute cellular rejection (ACR). In addition, improvements in immunosuppression have recently reduced the number and enhanced treatment of ACR episodes, enabling graft recovery.

OBJECTIVE

We analyzed immunosuppression protocols of leading transplantation centers in the last 5 years.

METHOD

We reviewed papers published in PubMed from major multivisceral and intestinal transplantation centers from 2006 to 2010 in adult recipients. The 211 adults transplanted in seven centers were divided into three groups according to the immunosuppression protocol used: protocol 1: daclizumab induction with tacrolimus and steroid maintenance; protocol 2: alemtuzumab and tacrolimus; and protocol 3: thymoglobulin and rituximab and tacrolimus.

RESULTS

Protocol 2 showed the lowest rate of ACR (34%). Protocols 1 and 3 displayed 54% and 48% ACR rates; respectively. However, protocol 1 patients developed only mild ACR, whereas those in protocols 2 and 3 developed moderate ACR in 26.3% and 11.7%, and severe ACR in 7.9% and 47% of cases, respectively. The infection rate was considerably lower in protocol 3 (7.4%). Protocols 1 and 2 showed infection rates of 62.5% and 52%, respectively. One-year patient survival rates were 70%, 79% and 81%, respectively. Three-year patient survival rates were 62%, 56%, and 78% for protocols 1, 2 and 3, respectively.

CONCLUSION

Protocol 2 was the strongest immunosuppressive regimen capable of reducing ACR rates when compared with the other protocols, but the strong effect resulted in high infection rate that impacts 1-year patient survival. Protocol 3 seems to be the best available one balancing ACR and infection rates.

Multivisceral transplantation: expanding indications and improving outcomes

INTRODUCTION

Multivisceral transplantation includes the simultaneous transplantation of multiple abdominal viscera including the stomach, duodenum, pancreas, and small intestine, with (multivisceral transplant, MVT) or without the liver (modified MVT, MMVT). This study reviews the changing indications and outcomes for this procedure over a 7-year period at a university medical center.

METHODS

This study is a retrospective case review of MVTs performed between 2004 and 2010 at a single center. All cases were either MVT or MMVT and included a simultaneous kidney transplant, if indicated. Graft failure was defined as loss of the graft or complete loss of function. Graft function was monitored by clinical function, laboratory values, and serial endoscopy with biopsy.

RESULTS

During the study period, 95 patients received 100 transplants including 84 MVT and 16 MMVT. There were 19 patients who received a simultaneous kidney graft. There were 24 pediatric and 76 adult recipients (range 7 months to 66 years). Indications included intestinal failure alone, intestinal failure with cirrhosis, complete portal mesenteric thrombosis, slow-growing central abdominal tumors, intestinal pseudoobstruction, and frozen abdomen. All patients received antibody-based induction immunosuppression with calcineurin inhibitor-based maintenance immunosuppression. At a median mortality adjusted follow-up of 25 months, 1- and 3-year patient survival is 72 % and 57 %. There was a learning curve with this complex procedure resulting in a 48 % patient survival during the period from 2004 to 2007, followed by a 70 % patient survival during the period from 2008 to 2010. Post-transplant complications included rejection (50 % MMVT and 17 % MVT), infection (>90 % first year), graft versus host disease (13 %), and post-transplant lymphoproliferative disorder (5 %).

CONCLUSION

Indications for MVT and MMVT have broadened to include patients with terminal conditions not amenable to other medical therapies such as slow-growing tumors of the mesenteric root, complete portomesenteric thrombosis, and abdominal catastrophes/frozen abdomen. Outcomes have improved over time with many patients returning to full functional status and enjoying long-term survival.

Humoral theory of transplantation: some hot topics

INTRODUCTION

Antibody is a major cause of allograft injury. However, it has not been routinely tested post-transplant.

SOURCES OF DATA

A literature search was performed using PubMed on the topics of 'antibody monitoring', 'autoantibody and allograft dysfunction' and 'prevention and treatment of antibody-mediated rejection (AMR)'.

AREAS OF AGREEMENT

Donor-specific antibody (DSA) monitoring not only helps to identify patients at risk of AMR, but also serves as a biomarker to personalize patient's maintenance immunosuppression. Development of autoantibody is a secondary response following primary tissue injury. Some autoantibodies are directly involved in allograft injury, while others only serve as biomarkers of tissue injury.

AREAS OF CONTROVERSY

It remains controversial whether DSA-positive patients without symptoms need to be treated. In addition, given the variation in study designs and patient's characteristics, there is discrepancy regarding which treatment regimens provide optimal clinical outcome in preventing/treating AMR.

GROWING POINTS

Efficacy of B-cell and/or antibody-targeted therapies in treating or preventing AMR would be better measured by the incorporation of antibody monitoring into current functional and pathological assays.

AREAS TIMELY FOR DEVELOPING RESEARCH

Research in B-cell targeted therapies to prevent and treat AMR is rapidly growing, which includes monoclonal antibodies against B-cell markers CD20, CD40, CD19, BlyS, etc. It requires extensive clinical research to determine the best approach to inhibit or delete antibody and how to balance the drug efficacy with safety.

Risk factors for native kidney dysfunction in patients with abdominal multivisceral/small bowel transplantation

Kidney dysfunction is a recognized complication after non-renal solid organ transplantation, particularly after intestinal transplant. In our study, we reviewed data on 33 multivisceral transplant (MVT)- and 15 isolated small bowel (ISB)-transplant patients to determine risk factors for kidney dysfunction. Kidney function was estimated by modified diet in renal disease (MDRD) and Schwartz formula for adults and children, respectively. Acute kidney injury (AKI) was defined as an increase in the serum Cr (sCr) greater than twofold. Kidney function declined significantly at one yr after transplantation with 46% of subjects showing an estimated GFR (eGFR) <60 mL/min. Patients with an episode of AKI were more likely to have reduced eGFR than those without AKI (p < 0.025). In linear regression analyses, age, pre-transplant sCr, eGFR at postoperative day (POD) 30, 90, 180, 270, and tacrolimus level at POD 7 showed significant correlation with one yr post-transplant eGFR (p < 0.05). Pediatric patients and patients with MVT had lesser decline in kidney function compared with adults or patients with ISB. In conclusion, risk factors for post-transplant kidney dysfunction in intestinal transplantation included age, pre-transplant sCr, AKI episode, eGFR at POD 30, 90, 180, 270, and tacrolimus level at POD 7.

Immunomodulatory nonablative conditioning regimen for B-cell lymphoid malignancies

Twenty-six patients with recurrent CD20(+) B-cell lymphoid malignancies received fludarabine, cyclophosphamide, and rituximab-based nonablative conditioning followed by either matched related (n = 18) or unrelated (n = 8) donor allogeneic stem cell transplantation (allo-SCT) between March 2008 and May 2011. Median age of patients at transplantation was 59 years (range, 41-64 years). At diagnosis, 20 (77%) had stage IV disease; 23 (88%) received ≥3 regimens, 14 (54%) received ≥4 regimens, and 4 (15%) had earlier autologous-SCT. All patients had either chemosensitive or stable disease and nine (35%) were in complete remission before transplantation. At the time of analysis, 17 patients were alive with an estimated 2-year overall survival and progression-free survival rate of 63% and nonrelapse mortality of 25%. Grade II to IV acute graft-vs-host-disease occurred in 8 (31%) and chronic graft-vs-host-disease in 6 (23%) patients (extensive, n = 3). Causes of death include progressive disease in four, acute graft-vs-host-disease in two (both after receiving donor lymphocyte infusion for mixed chimerism with residual disease), infection in one, and other (e.g., substance abuse, leukoencephalopathy) in two. Six patients required rehospitalization within 100 days of SCT (mean = 10 days; range, 3-18 days). Our data support fludarabine, cyclophosphamide, and rituximab-based nonablative conditioning allo-SCT in CD20(+) B-cell lymphoid malignancies and it is time to compare this regimen with an alternative reduced-intensity conditioning regimen in B-cell malignancies.

Strategies to prevent EBV reactivation and posttransplant lymphoproliferative disorders (PTLD) after allogeneic stem cell transplantation in high-risk patients

Epstein-Barr virus (EBV)-associated postallogeneic stem cell transplantation (SCT) lymphoproliferative disorder (PTLD) is often life threatening. The risk of EBV reactivation is highest in older patients, T cell-depleted SCT (in vivo or vitro), and in unrelated or mismatched SCT. Cumulative numbers of patients with EBV reactivation and PTLD are rising as more patients at high risk for EBV reactivation and PTLD are receiving allo-SCT. Novel but easily applicable strategies are needed to prevent EBV reactivation and PTLD to serve the needs of the increasingly enlarging population of high-risk SCT recipients across the globe.

Induction therapy: why, when, and which agent?

The long-term outcome of paediatric transplantation has improved over the last decade with an increase in the armamentarium of immunosuppressive agents. However, the battle against the hostile immune response at the time of and after transplantation continues. Induction therapy can reduce early injury, to optimize the long-term allograft survival. The goal of induction immunosuppression in paediatric transplantation is to permit the use of lower doses of maintenance immunosuppressive agents without increased rates of acute allograft rejection and chronic allograft damage. The aim of this review is to summarize the current literature relating to the use of antibody agents for induction in paediatric solid organ transplantation.

Graft-vs-host disease after small bowel transplantation in children

PURPOSE

Graft-vs-host disease (GVHD) is a rare complication of transplantation of organs rich in immunocompetent cells. The goal of this study was to report the features of GVHD after small bowel transplantation (SBTx) in children.

METHODS

The study involved a retrospective review of patients undergoing SBTx between 1999 and 2009 who had GVHD.

RESULTS

Of 46 children receiving 52 intestinal grafts (2 liver-intestine and 3 multivisceral), 5 (10%) developed GVHD. Median age at transplant was 42 (19-204) months. Baseline immunosupression consisted of tacrolimus and steroids supplemented with thymoglobulin (n = 2) or basiliximab (n = 3) for induction. Median time between transplantation and GVHD was 47 (16-333) days. All patients had generalized rash, 2 had diarrhea, and 2 had respiratory symptoms. Other symptoms were glomerulonephritis (n = 1) and conjunctivitis (n = 1). Four developed severe hematologic disorders. The diagnosis was confirmed by skin biopsy in 4 patients and supported by chimerism studies in two. Colonoscopy and opthalmoscopic findings were also suggestive in one. Treatment consisted of steroids and decrease of tacrolimus, with partial response in four. Other immunosuppressants were used in refractory or recurrent cases. Three patients died within 4 months after diagnosis.

CONCLUSION

Graft-vs-host disease is a devastating complication of SBTx, with high mortality probably associated with severe immunologic dysregulation.

Intensive pharmacological immunosuppression allows for repetitive liver gene transfer with recombinant adenovirus in nonhuman primates

Repeated administration of gene therapies is hampered by host immunity toward vectors and transgenes. Attempts to circumvent antivector immunity include pharmacological immunosuppression or alternating different vectors and vector serotypes with the same transgene. Our studies show that B-cell depletion with anti-CD20 monoclonal antibody and concomitant T-cell inhibition with clinically available drugs permits repeated liver gene transfer to a limited number of nonhuman primates with recombinant adenovirus. Adenoviral vector-mediated transfer of the herpes simplex virus type 1 thymidine kinase (HSV1-tk) reporter gene was visualized in vivo with a semiquantitative transgene-specific positron emission tomography (PET) technique, liver immunohistochemistry, and immunoblot for the reporter transgene in needle biopsies. Neutralizing antibody and T cell-mediated responses toward the viral capsids were sequentially monitored and found to be repressed by the drug combinations tested. Repeated liver transfer of the HSV1-tk reporter gene with the same recombinant adenoviral vector was achieved in macaques undergoing a clinically feasible immunosuppressive treatment that ablated humoral and cellular immune responses. This strategy allows measurable gene retransfer to the liver as late as 15 months following the first adenoviral exposure in a macaque, which has undergone a total of four treatments with the same adenoviral vector.

Present prospects and future perspectives of intestinal and multivisceral transplantation

PURPOSE OF REVIEW

This article reviews the most current indications, technical aspects and results of intestinal and multivisceral transplantation.

RECENT FINDINGS

The introduction of induction therapy in the past 8 years, combined with advancements on surgical technique and clinical management, was vital for the improvement in patient and graft survival.

SUMMARY

Intestinal transplantation is now a viable option for patients with intestinal failure who have failed parenteral nutrition. The improvement in the survival of intestinal and multivisceral transplant recipients has extended its use to selected patients with neoplastic disease, extensive splanchnic thrombosis and abdominal catastrophes.