Successful treatment of posttransplant lymphoproliferative disease with prolonged rituximab treatment in intestinal transplant recipients

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.

Post-transplant lymphoproliferative disorder in pediatric intestinal transplant recipients: A literature review

Intestinal transplantation is a successful treatment for children with intestinal failure, but has many potential complications. PTLD, a clinically and histologically diverse malignancy, occurs frequently after intestinal transplantation and can be fatal. The management of this disease is particularly challenging. The rejection-prone intestinal allograft requires high levels of immunosuppression, a precondition for PTLD. While EBV infection clearly plays a role in disease pathogenesis, the relatively naïve immune system of children is another likely contributor. As a result, pediatric intestine recipients have a higher risk of developing PTLD than other solid organ recipients. Other risk factors for disease development such as molecular and genomic changes that precipitate malignant transformation are not fully understood, especially among children. Studies on adults have started to describe the molecular pathogenesis of PTLD, but the genomic landscape of the malignancy remains largely undefined in pediatric intestinal transplant patients. In this review, we describe what is known about PTLD in pediatric patients after intestinal transplant and highlight current knowledge gaps to better direct future investigations in the pediatric population.

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.

Clinical practice guidelines--Nursing management for pediatric patients with small bowel or multivisceral transplant

PURPOSE

Small bowel or multivisceral transplant is a relatively new treatment for irreversible intestinal damage, and no published practice guidelines exist. The purpose of this article is to report evidence regarding the best plan of care to achieve adequate nutrition and appropriate development for children.

DESIGN AND METHODS

An integrative review was conducted with 54 articles related to management of this transplant population. A nine-member nursing team integrated the findings.

PRACTICE IMPLICATIONS

This resulting guideline represents the best research and best practices on which to base staff education and competency validations to manage this medically fragile patient population.

Managing post-transplant lymphoproliferative disorders in solid-organ transplant recipients: a review of immunosuppressant regimens

Post-transplant lymphoproliferative disorders (PTLD) are a heterogeneous group of potentially life-threatening complications that occur after solid organ and bone marrow transplantation. Risk factors for acquiring PTLD are type of organ transplanted, age, intensity of immunosuppression, viral infections such as Epstein-Barr virus (EBV) and time after transplantation. Due to a dearth of well designed prospective trials, treatment for PTLD is often empirical, with reduction in immunosuppression accepted as the first step. Rituximab, a monoclonal antibody directed against the CD20 antigen of immature B cells, is often used as monotherapy after reduction in immunosuppression, although this is associated with a high risk of relapse if patients have at least one of the following risk factors: age greater than 60 years, elevated lactate dehydrogenase levels and Eastern Cooperative Oncology Group Score between 2 and 4. For such patients, rituximab should be considered in combination with CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone), particularly if high-grade PTLD is present. Although widely prescribed, the use of ganciclovir for PTLD remains controversial as EBV-transformed cells lack the thymidine kinase necessary for ganciclovir activation. Newer antivirals that combine ganciclovir with activators of cellular thymidine kinase have shown promising results in preclinical studies. In the absence of controlled trials, surgery may be indicated for localized disease and radiotherapy for patients with impending spinal cord compression or disease localized to the central nervous system or orbit. Future interventions may include adoptive immunotherapy, intravenous immunoglobulin, mammalian target of rapamycin inhibitors, monoclonal antibodies to interleukin-6 and galectin-1, and even EBV vaccination. Although several trials are in progress, it is necessary to wait for the long-term outcome of these studies on risk of PTLD relapse.

Current status of intestinal transplantation

The prognosis of short gut syndrome has improved dramatically in the past few decades through the development of total parenteral nutrition (TPN). However, TPN-related complications still produce major problems for such patients. Intestinal transplantation can significantly improve patients' prognosis and increase their quality of life. The international intestinal transplant registry is updated every other year in an international small bowel transplant symposium. In this report we review the indications, procedures, management, and current status of intestinal transplantation based on the 11th International Small Bowel Transplant Symposium held in Bologna in 2009. The major findings of international studies have shown that optimization of the following factors may contribute to better outcomes: advancement of surgical techniques, new immunosuppressive techniques, improvement of postsurgical management, adequate timing of transplantation, and refined selection of candidates. Ideally, intestinal transplantation will be established as a standard therapy for intestinal failure and secondary multiorgan failure by improving the long-term survival and quality of life for patients receiving such transplants.

Update on EBV monitoring, detection and therapy in PTLD after solid organ transplant

EBV remains an important cause of morbidity and mortality in solid organ transplant (SOT) recipients. Post-transplant lymphoproliferative disorder is the most severe complication of EBV infection in SOT patients. While EBV viral load monitoring can be used to predict SOT patients at high risk of post-transplant lymphoproliferative disorder (most effectively for patients who are EBV seronegative prior to transplant), interpretation and management of these results may be confusing and can be complex. Monitoring to guide preemptive reduced immunosuppression has contributed to the decreased incidence of post-transplant lymphoproliferative disorder in SOT recipients. For the treatment of post-transplant lymphoproliferative disorder, increasing evidence supports the use of the anti-CD20 antibody rituximab. However, experience to date suggests that use of this agent may not prevent recurrence of tumor or improve cell-mediated immune responses to EBV. Future investigation of EBV-specific T-cell responses as an adjunct to monitoring and adoptive transfer of EBV-specific cytotoxic T lymphocytes appear likely in further attempts to limit the consequences of EBV infection in the SOT population.

Management of post-transplant lymphoproliferative disorder in adult solid organ transplant recipients - BCSH and BTS Guidelines

A joint working group established by the Haemato-oncology subgroup of the British Committee for Standards in Haematology (BCSH) and the British Transplantation Society (BTS) has reviewed the available literature and made recommendations for the diagnosis and management of post-transplant lymphoproliferative disorder in adult recipients of solid organ transplants. This review details the therapeutic options recommended including reduction in immunosuppression (RIS), transplant organ resection, radiotherapy and chemotherapy. Effective therapy should be instituted before progressive disease results in declining performance status and multi-organ dysfunction. The goal of treatment should be a durable complete remission with retention of transplanted organ function with minimal toxicity.

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.

Posttransplant lymphoproliferative disorder in adult liver transplant recipients: a report of seventeen cases

Posttransplant lymphoproliferative disorder (PTLD) is a major complication of liver transplantation, but previous descriptions have been limited to case reports and small case series. We report a retrospective analysis of 17 consecutive cases of PTLD associated with liver transplantation. The median age at PTLD diagnosis was 47 years (range 19 - 63) with a median time of 25 months from liver transplantation to PTLD diagnosis (range 3 - 75). PTLD location was frequently extranodal (71%) and involved the transplanted liver (41%). PTLD histology consisted of nine (53%) monomorphic and eight (47%) polymorphic disease. EBV was present by in situ hybridization in 11 (79%) of 14 cases evaluated. Initial therapy included reduction in immunosuppression (RI) alone in 13 (76%) of 17 patients, resulting in 6 (46%) complete responses (CR) and 7 (54%) progressive disease (PD). Monoclonal CD20 antibody (rituximab) and CHOP chemotherapy were used as initial therapy or as second line after RI failure. Currently, five patients (29%) are alive in CR. Although detection and treatment of PTLD in liver transplant recipients remains problematic and upfront mortality is still high, long-term survival is possible. Further studies are necessary to better define treatment strategies.

Successful prolonged rituximab treatment for post-transplant lymphoproliferative disorder following living donor liver transplantation in a child

PTLD is a serious complication of immunosuppression in solid organ transplant recipients. The incidence of PTLD is significantly higher in pediatric recipients than in adult because children are often EBV-seronegative and they may develop primary EBV infection after transplantation. We herein describe a case of GI-PTLD who achieved a complete remission by prolonged rituximab, a chimeric monoclonal antibody against CD20, mono-therapy. A one-yr-old female underwent a LDLT for liver failure after having previously undergone the Kasai procedure for biliary atresia. At sixty days following the transplantation, GI-PTLD developed. Withdrawal of immunosuppression and a surgical resection were thus performed. A histopathological examination of tumor revealed atypical medium to large cell lymphoid proliferation with strong CD20 immunopositivity indicating their B-cell origin. Polymorphic PTLD was diagnosed. Rituximab was administered at a dose of 375 mg/m2 once a week, and the monotherapy resulted in a complete remission after 34 administrations. Based on this case, rituximab appears to be beneficial as a first-line therapy for PTLD.

Primary small-bowel non-Hodgkin's lymphoma: a study of clinical features, pathology, management and prognosis

The records of 34 patients diagnosed with primary small bowel non-Hodgkin's lymphoma during a 10-year period between January 1996 and December 2005, including 27 cases for which complete follow-up records were available, were studied. Abdominal pain (70.6% of patients) was the main presenting symptom, followed by intestinal obstruction (38.2%). The most common primary site was the ileum (58.8%), followed by the jejunum (26.5%) and duodenum (17.6%); one case had tumours at two sites in the small bowel. Twenty-seven patients had small bowel B-cell lymphoma (24 diffuse large B-cell lymphoma; three mucosa-associated lymphoid tissue B-cell lymphoma) and seven patients had small bowel T-cell lymphoma. Cumulative survival in patients with small bowel B-cell lymphoma was higher than that in patients with small bowel T-cell lymphoma. Data on 16 male and eight female patients with diffuse large B-cell lymphoma showed that 62.5% of these patients presented with disease stages I or II and 37.5% with stages III or IV. Cumulative survival in patients at stages IE or IIE was significantly higher than that of patients at stages IIIE or IVE. Four of five patients who died from diffuse large B-cell lymphoma had abnormal levels of lactate dehydrogenase and serum albumin.

Italian Experience in Adult Clinical Intestinal and Multivisceral Transplantation: 6 Years Later

PATIENTS AND METHODS

Between December 2000 and November 2006, 28 isolated intestinal transplants and nine multivisceral transplants (five with liver) from cadaveric donors have been performed for short gut syndrome (n = 15), chronic intestinal pseudo-obstruction (n = 10), Gardner's syndrome (n = 9), radiation enteritis (n = 1), intestinal atresia (n = 1), and massive intestinal angiomatosis (n = 1). Indications for transplantations were: loss of venous access, recurrent sepsis due to central line infection, and/or major electrolyte and fluid imbalance. Liver dysfunction was present in 19 cases. All patients were adults of median age at transplant of 34.7 years and mean weight 59.6 kg. All recipients were on total parenteral nutrition for a mean time of 38.8 months. Mean donor/recipient body weight ratio was 1.1.

RESULTS

The mean follow-up was 892 +/- 699 days. Twenty-five patients were alive (67.5%) with 3-year patient survivals of 70% for isolated intestinal transplantations and 41% for the multivisceral transplantations (P = .01). The mortality rate was 32.5% with losses due to sepsis (63%) or rejection. Our 3-year graft survival rates were 70% for isolated intestinal transplantations and 41% for multivisceral transplantations (P = .02); graftectomy rate was 16%. These were 88% of grafts working properly with patients on regular diet with no need for parenteral nutrition.

DISCUSSION AND CONCLUSIONS

Induction therapy has reduced the doses of postoperative immunosuppressive agents, especially in the first period, lowering the risk of renal failure and sepsis, mucosal surveillance protocol for early detection of rejection dramatically reduced the number of severe acute chronic rejections.

Twenty-five consecutive isolated intestinal transplants in adult patients: a five-yr clinical experience

PATIENTS AND METHODS

Between December 2000 and December 2005, 25 isolated intestinal transplants from cadaveric donors have been performed for short gut syndrome (short bowel syndrome, 52%), chronic intestinal pseudo-obstruction (24%), Gardner syndrome (16%), radiation enteritis (4%) and massive intestinal angiomatosis (4%). Indications for transplantation were: loss of venous access, recurrent sepsis due to central line infection, major electrolyte and fluid imbalance. Liver dysfunction was present in 13 cases. All patients were adult; median age was 36.3 yr and mean weight at transplantation 61.6 kg. All recipients were on life-threatening parenteral nutrition for a mean time of 23.7 months. Mean donor/recipient body weight ratio was 1.08. Rejection monitoring was accomplished by graft ileoendoscopies and intestinal biopsies through the temporary ileostomy. Our immunosuppressive regimen was based on induction therapy with three different protocols: daclizumab for induction, tacrolimus and steroids as maintenance therapy; alemtuzumab for induction and low-dose tacrolimus as maintenance; thymoglobulin for induction and maintenance based on low-dose tacrolimus. Closure of the abdomen at the end of transplantation represented a technical problem with several options performed: graft reduction, only skin closure, prothesic meshes, abdominal closure in two steps, cutaneous flaps and abdominal wall transplant in one case.

RESULTS

The mean hospital stay was 37 days. The mean follow-up 27 months. Twenty patients are alive (80%) with two- and five-yr patient survival rate of 80% and 66%; mortality rate was 20% due to sepsis in all cases. Our two- and five-yr graft survival rate is 76% and 64%, graftectomy rate was 16%. Sixteen grafts are working properly, with no need of parenteral nutrition. We diagnosed 35 mild acute cellular rejection (ACRs), seven moderate ACRs and three severe ACRs (two needed graftectomy). We experienced two episodes of chronic rejection biopsy-proven. Rapamicine was added in case of renal failure or biopsy-proven intestinal rejection. Graft-vs.-host disease was not seen in our series while post-transplant lymphoproliferative disease in two cases. After discharge, the most common indication for medical support was dehydration. The abdominal wall transplant did not experience any rejection.

DISCUSSION AND CONCLUSIONS

Induction therapy has reduced the amount of postoperative immunosuppressive agents, especially in the first period, lowering the risk of renal failure and sepsis and the mucosal surveillance protocol for early detection of rejection dramatically reduced the number of severe ACR.

La greffe intestinale

Even though surgical techniques for isolated intestine, liver-intestine, and multivisceral transplantations were developed in the 1960's, very few patients were transplanted before 1990 because initial immunosuppression regimens were insufficient, making intestine transplantation impossible. Intestine transplantation resulted in death in most patients within days or months. The discouraging results of the first clinical trials were due to technical complications, sepsis, and the failure of conventional immunosuppression to control rejection. By 1990 the development of tacrolimus-based immunosuppression and improved surgical techniques, the increased array of potent immunosuppressive medications, infection prophylaxis, and suitable patient selection helped improve actuarial graft and patient survival rates for all types of intestine transplantation. The aims of this review are to describe the current status of intestine transplantation including the underlying diseases and conditions that may be indications for intestine transplantation, to identify patient populations for this indication, to provide key steps for patient evaluation, to summarize current recommendations for immunosuppression, to list the most common postoperative complications, and to discuss the international experience of small bowel transplantation compiled and analyzed by the International Intestine Transplant Registry since 1985.

Small intestine transplantation today

INTRODUCTION

Intestinal transplantation has become a life-saving therapy in patients with irreversible loss of intestinal function and complications of total parenteral nutrition.

DISCUSSION

The patient and graft survival rates have improved over the last years, especially after the introduction of tacrolimus and rapamycin. However, intestinal transplantation is more challenging than other types of solid organ transplantation due to its large amount of immune competent cells and its colonization with microorganisms. Moreover, intestinal transplantation is still a low volume procedure with a small number of transplanted patients especially in Germany. A current matter of concern is the late referral of intestinal transplant candidates.

CONCLUSION

Thus, patients often present after onset of life-threatening complications or advanced cholestatic liver disease. Earlier timing of referral for candidacy might result in further improvement of this technique in the near future.

Intestinal and multivisceral transplantation in children

OBJECTIVE

To describe a single-center experience of pediatric intestinal transplantation (Itx) and to provide an overview of the children who underwent this procedure along with their outcomes.

SUMMARY BACKGROUND DATA

Pediatric Itx presents multiple challenges because of the very young ages at which patients require transplantation and their higher susceptibility to infectious complications.

METHODS

We have performed 141 Itx in 123 children with a median age of 1.37 years. Primary grafts included isolated intestine (n = 28), liver and intestine (n = 27), multivisceral (n = 61), and multivisceral without the liver (n = 7). Two protocol modifications were introduced in 1998: daclizumab induction and frequent rejection surveillance. In 2001, indications for multivisceral transplantation were expanded, and induction with Campath-1H was introduced.

RESULTS

Actuarial patient survival at 1 and 3 years for group 1 (January 1994 to December 1997, n = 25), group 2 (January 1998 to March 2001, n = 29), group 3a (April 2001 to present, daclizumab, n = 51), and group 3b (April 2001 to present, Campath-1H, n = 18) was 44%/32%, 52%/38%, 83%/60%, and 44%/44%, respectively (P = 0.0003 in favor of group 3a). Severe rejection implied a dismal prognosis (65% mortality at 6 months). Observed incidence of severe rejection in groups 1, 2, 3a, and 3b was 32%, 24%, 14%, and 11%, respectively. In multivariable analysis, use of a multivisceral (with or without liver) transplant (P = 0.002), induction with daclizumab (P = 0.005), patient at home prior to transplant (P = 0.007), and age at transplant > or =1 year (P = 0.02) favorably influenced patient survival. Multivisceral transplant was protective with respect to the mortality rate due to rejection, while an older age at transplant was associated with both a lower incidence rate of developing respiratory infection and lower risk of mortality following the respiratory infection. Survivors are off parenteral nutrition and have demonstrated significant growth catch-up.

CONCLUSIONS

Itx in children still is a high-risk procedure but has now become a viable option for children who otherwise have no hope for survival. Control of respiratory infection is of particular importance in the younger children.

Intestinal transplantation in The Netherlands: first experience and future perspectives

Intestinal transplantation for intestinal failure is no longer an experimental procedure, but an accepted treatment for patients who fail total parenteral nutrition (TPN) therapy. Early referral for evaluation for small bowel transplantation has to be considered in patients with permanent intestinal failure who have occlusion of more than two major veins, frequent line-related septic episodes, impairment of liver function or an unacceptable quality of life. With the increased experience in post-transplant patient care and newer forms of induction (thymoglobulin, IL-2 receptor antagonists) and maintenance (tacrolimus) therapies the 1-year graft survival has increased to 65% for isolated and to 59% for liver/small bowel transplantation, and is further improving. Rejection, bacterial, fungal and viral (CMV, EBV) infection, post-transplant lymphoproliferative disease (PTLD) and graft versus host disease (GvHD) are the most common complications after intestinal transplantation. Although most of the long-term survivors are TPN-independent and have a good quality of life, the risk of the procedure and long-term adverse effects of immunosuppressive medication limits small bowel, or liver/small bowel transplantation only to patients with severe complications of TPN therapy.

Central nervous system lymphoproliferative disorder in pediatric kidney transplant recipients

Post-transplant lymphoproliferative disorder (PTLD) is a complication of transplantation resulting from impaired immune surveillance because of pharmacologic immunosuppression. We present two cases of central nervous system (CNS) PTLD in children on calcineurin-inhibitor free immunosuppression with dramatically different presentations and outcomes. One patient had brain and spinal cord lymphoma with a rapid and fatal course. The other patient had brain and ocular PTLD that responded to multimodal therapy with reduction of immunosuppression, high-dose steroids, and rituximab given in a dose-escalation protocol. This protocol may have enhanced the penetration of rituximab into the CNS. We review the literature on CNS and ocular PTLD and elaborate on the treatments available for both diseases.

Post-transplantation lymphoproliferative disorders localizing to the gastrointestinal tract after liver transplantation: report of five pediatric cases

Post-transplantation lymphoproliferative disorder (PTLD) is a life-threatening complication of organ transplantation. PTLD can occur in every kind of organ transplantation. From July 1992 to July 2004, five patients were diagnosed at our transplantation center with PTLD after pediatric liver transplantation. During this period, there were 52 pediatric patients (<18 yr) receiving an orthotopic liver transplantation (OLT) at our center. All five patients had transmural gastrointestinal (GI) PTLD, which occurred mostly in the stomach and duodenum. Epstein-Barr virus (EBV) in situ was demonstrated in each case. EBV viral load was noted to be an important risk factor. Treatment included dose reduction of immunosuppressants and anti-CD20 antibody infusion. Chemotherapy, including cyclophosphamide, doxorubicin, vincristine, and prednisolone, was given to three patients. Four patients have survived more than 10 months until now after treatment. The one who was unresponsive to chemotherapy and anti-CD20 antibody had diffuse metastasis and died of systemic candidiasis. In our series, each PTLD involved the GI tract. The mechanism of this phenomenon is unclear, but these five cases indicate the high incidence of PTLD in pediatric solid organ transplantation.

Rituximab, an anti-cd20 monoclonal antibody: history and mechanism of action

Rituximab, chimeric anti-human CD20, is approved for treatment of B-cell lymphoma in adults. It is being used experimentally in other various immune-related diseases such as immune thrombocytopenic purpura, systemic lupus erythematosus, myasthenia gravis and rheumatoid arthritis. In transplant recipients, it is used for treatment of post-transplant lymphoproliferative disease, to anecdotally reduce pre-formed anti-HLA and anti-ABO antibodies and for the prevention and treatment of acute rejection. This article primarily reviews the science behind rituximab: its history, pharmacokinetics and potential mechanism of action. A need for controlled clinical trials is clearly indicated before the widespread use of this drug in transplant.

Management of patients with post-transplant lymphoproliferative disorder: the role of rituximab

Post-transplant lymphoproliferative disorder (PTLD) is a serious complication of solid organ and bone marrow transplantations. Rituximab (Rituxan, Mabthera), a chimeric monoclonal antibody to the CD20 antigen on the surface of B-cell lymphocytes, has been used increasingly in the treatment of PTLD. Rituximab was initially approved for the treatment of low-grade non-Hodgkin lymphomas, but multiple case studies, retrospective analyses, and phase II trials demonstrate the benefit of rituximab in PTLD. This paper reviews the current data on rituximab and its promising role in the management of PTLD.

Treatment of PTLD with rituximab or chemotherapy

Information regarding treatment of post-transplant lymphoproliferative disease (PTLD) beyond reduction in immunosuppression (RI) is limited. We retrospectively evaluated patients receiving rituximab and/or chemotherapy for PTLD for response, time to treatment failure (TTF) and overall survival (OS). Thirty-five patients met inclusion criteria. Twenty-two underwent rituximab treatment, with overall response rate (ORR) 68%. Median TTF was not reached at 19 months and estimated OS was 31 months. In univariable analysis, Epstein-Barr virus (EBV) positivity predicted response and TTF. LDH elevation predicted shorter OS. No patient died of rituximab toxicity and all patients who progressed underwent further treatment with chemotherapy. Twenty-three patients received chemotherapy. ORR was 74%, median TTF was 10.5 months and estimated OS was 42 months. Prognostic factors for response included stage, LDH and allograft involvement by tumor. These factors and lack of complete response (CR) predicted poor survival. Twenty-six percent of the patients receiving chemotherapy died of toxicity. Rituximab and chemotherapy are effective in patients with PTLD who fail or do not tolerate RI. While rituximab is well tolerated, toxicity of chemotherapy is marked. PTLD patients requiring therapy beyond RI should be considered for rituximab, especially with EBV-positive disease. Chemotherapy should be reserved for patients who fail rituximab, have EBV-negative tumors or need a rapid response.

Gastrointestinal tract ulcers in pediatric intestinal transplantation patients: etiology and management

One of the observed complications in patients after intestinal transplantation is the occurrence of ulcers in the native or transplanted gastrointestinal tract. Previous reports have described the appearance of ulcers but have not described any systemic approach to accurately diagnose the etiology of the ulcer. We evaluated 112 intestinal transplantation patients at our institution, in which endoscopic examination identified ulcer formation in 11 patients. No common or defining demographic or clinical variables were found in the patients with ulcers. Biopsies were obtained from the ulcer edge as well as the intervening mucosa. The most common changes in the ulcers were compatible with post-transplant lymphoproliferative disorder (PTLD), acute rejection, and viral infections. These changes could occur simultaneously and retrospective analysis showed that ulcers could have concomitant etiologies. Endoscopically directed biopsies of ulcer edges often displayed morphologic changes compatible with acute rejection of the graft. Some patients were treated for rejection based on the changes within the mucosa outside the ulcer bed, and they responded with resolution of the ulcers. Our findings demonstrate that PTLD and acute rejection are the most common causes of chronic ulcer formation and reinforce the concept that biopsy samples should be collected simultaneously from both the ulcer edge and intervening mucosa.

Rituximab therapy is effective for posttransplant lymphoproliferative disorders after solid organ transplantation: results of a phase II trial

BACKGROUND

Posttransplant lymphoproliferative disorders (PTLD) remain an uncommon complication of solid organ transplantation with a high mortality rate reported after conventional therapies. Alternative treatments such as rituximab have been explored.

METHODS

Eleven patients with PTLD, who were CD20 positive, received an intravenous dose of rituximab, 375 mg/m2, weekly x 4 weeks, repeated every 6 months for 2 years in responding patients. The median age of the patients was 56 years (range, 43-68 yrs), and 9 patients were male. The type of solid organ transplantation that these patients received included lung (five patients), kidney (four patients), heart (one patient), and kidney/pancreas (one patient). The median time from transplantation to a PTLD diagnosis was 9 months (range, 1-122 mos). Diagnostic B-cell histology was diffuse large cell lymphoma or polymorphous process. No patient had bone marrow or central nervous system involvement. Primary extranodal disease was noted in 82% of patients. Immunosuppressive therapy was decreased at the time of diagnosis.

RESULTS

Rituximab was well tolerated, with mild infusional blood pressure alterations noted in two patients. The median follow-up period was 10 months (range, 1-32 mos). The overall response rate was 64%, with 6 complete responses (CR), 1 partial response, 2 cases of progressive disease, and 2 deaths. The median duration of CR was 8 months (range, 2-19+ mos). The median time to treatment failure was 10 months (range, 5-25+ mos). The median survival was 14 months (range, < 1-32+ mos). Four patients were alive at the time of last follow-up.

CONCLUSIONS

Single-agent rituximab may offer a response and survival advantage in patients with PTLD. Further evaluation of rituximab in these disorders, potentially in combination with other therapies, is warranted.

Monoclonal antibodies and fusion proteins in medicine

Humanized antibodies and decoy receptors have been introduced in clinical practice to treat malignancies and systemic autoimmune disease because they ablate specific cells or disrupt pathogenic processes at distinct points. Reported clinical responses offer hope to treatment-resistant patients, particularly those with lymphomas and rheumatic diseases. Side effects from the use of biologic agents include lymphokine release syndrome, reactivation of tuberculosis, and immunosuppression. Further insights are needed regarding limitation of adverse effects, correct use in conjunction with existing drugs, and treatment of patients in whom resistance develops.

Quantitative EBV viral loads and immunosuppression alterations can decrease PTLD incidence in pediatric liver transplant recipients

Epstein-Barr virus (EBV) is a common viral infection in pediatric liver transplant patients and can lead to development of post-transplant lymphoproliferative disorder (PTLD). Differing studies have used immunosuppression reduction, antiviral medications or i.v. CMV-immunogloublin for EBV prevention and treatment. The purpose of this study was to determine whether implementation of a protocol for frequent EBV monitoring and EBV viral load-driven immunosuppression reduction could decrease the incidence of PTLD in our patient population. All data were prospectively collected between 2001 and 2004 at a single institution. Seventy-three patients were entered into the study. Patients were divided into a historical control group (pre-2001, 30 patients) and a treatment group (post-2001, 43 patients). Approximately 1271 blood samples of 73 patients were collected between 2001 and 2004. Eleven out of 43 patients received immunosuppression tapering due to high EBV viral loads (>4000 copies/microg DNA). One patient developed allograft rejection after immunosuppression modulation. Prior to 2001, the incidence of PTLD at our institution was 16%. After instituting a protocol for EBV monitoring, the incidence of PTLD decreased to 2% (p-value<0.05). These findings illustrate that frequent EBV viral load monitoring and preemptive immunosuppression modulation have an integral role in preventing PTLD in the pediatric liver transplant population.

Treatment of EBV-related post-renal transplant lymphoproliferative disease with a tailored regimen including EBV-specific T cells

The treatment of EBV-associated post-transplant lymphoproliferative disease (PTLD) poses a considerable challenge. Efforts have been made to define regimens based on combination of the available therapeutic agents, chosen and tailored on a patient-by-patient basis, with the aim of augmenting event-free patient and graft survival. Recently, autologous EBV-specific cytotoxic T-lymphocytes (CTL) have proved effective in enhancing EBV-specific immune responses and reducing viral load in organ transplant recipients with active infection. We investigated the use of a tailored combined approach including autologous EBV-specific CTL for the treatment of EBV-related PTLD developing after pediatric kidney transplantation. Five patients with disseminated monoclonal (n = 3) or localized polyclonal (n = 2) PTLD unresponsive to reduction of immunosuppression were enrolled. The patients with disseminated PTLD received 4-5 courses of reduced-dosage polychemotherapy, accompanied by rituximab on the first day of each course, while localized disease was removed surgically. At treatment completion, autologous EBV-specific CTL were infused. All patients showed a complete response to treatment, without therapy-related toxicity or rejection, and persist in remission with good renal function at a median follow-up of 31 months. These preliminary results suggest that a combined chemoimmunotherapy regimen including virus-specific T-cells is well tolerated and potentially effective as first-line treatment of EBV-related PTLD.

Rapid response to rituximab in a pediatric liver transplant recipient with post-transplant lymphoproliferative disease and maintenance with sirolimus monotherapy

A 12-yr-old girl with end-stage renal disease secondary to primary hyperoxaluria type I received a living related (left lateral segment) liver transplant from her brother as the first step of a staged liver and kidney transplant. Renal transplantation was planned for a later date from the same donor. Nine weeks after transplantation she developed polymorphic PTLD of the tonsils and adenoids. Initial treatment with surgical resection and withdrawal of immunosuppression was insufficient as she developed recurrence of the PTLD lesion 1 wk after surgical resection and reduction of immunsuppression. Treatment with the chimeric monoclonal anti CD20 antibody, rituximab (Mabthera, Hoffman-La Roche AG, Grenzach-Whylen, Germany), resulted in quick response and complete recovery from PTLD within 2 wk, with no recurrence up to 8 months after treatment. Rejection prophylaxis was successfully achieved with Sirolimus (Rapamune, Wyeth Pharmaceuticals Inc., Philadelphia, PA, USA) monotherapy, with no episodes of acute rejection.

Epstein-Barr virus-associated lymphoma in Crohn's disease

Although no increased risk of developing lymphoproliferative disorders has been observed in population-based studies of patients with Crohn's disease, the possibility has been suggested in the subset of patients previously treated with thiopurine metabolites and suffering from concomitant Epstein-Barr virus infection. A few cases of lymphomas have occurred in patients with Crohn's disease treated with infliximab, only one of whom showed the presence of the Epstein-Barr virus genome. We here describe the case of a patient with steroid-dependent ileal Crohn's disease treated with azathioprine and a single infusion of infliximab, who developed a diffuse large B cell ileal lymphoma. Epstein-Barr virus genome was detected in the neoplastic cells by means of polymerase chain reaction. Epstein-Barr virus may be detected in the neoplastic tissues of lymphomas of patients with Crohn's disease treated with immunosuppressants and infliximab. The identification of such cases may help to define the frequency of this association and how to manage the lymphoproliferative disorder.

EBV-negative lymphoproliferative disease with hyper-IgA, in a child with combined liver and small bowel transplantation

A 4-year-old boy presented 14 months after liver and small bowel transplantation with fever, diarrhea, elevated liver enzymes, thrombocytopenia and autoantibodies. Total gammaglobulins level was normal but the level of plasma IgA1 was very high. The blood PCR for Epstein-Barr virus (EBV) was negative. The ileal biopsy disclosed a lymphoplasmacytic infiltration. The EBER probe was negative on the small bowel biopsies. The child was considered as suffering from a non-EBV-induced posttransplant lymphoproliferative disorder (PTLD). The high IgA level was presumed to be secreted by proliferating plasma cells in the transplanted bowel. Immunosuppression was reduced; but the efficacy was incomplete and an anti-CD20 antibody was added. There was complete resolution of symptoms and normalization of the IgA level. As IgA1 is mostly of intestinal origin, this unusual presentation of PTLD should lead to a high suspicion of a small bowel proliferating process.

Monoclonal antibodies as therapeutic agents for cancer

Targeted therapies are the focus of much research in oncology. After the development of imatinib for the treatment of chronic myeloid leukaemia, biological therapies that target tumour-associated antigens give hope for improvement of survival in many cancers. At the American Society of Clinical Oncology (ASCO) conference in 2003, data for the antibodies bevacizumab and cetuximab highlighted promising results in clinical trials, including an improvement in survival for metastatic colorectal cancer. Positive results for other antibodies in various stages of clinical development provide hope that anticancer antibodies will have an effect on clinical oncology practice in the next 10 years.

The use of rituximab, anti-CD20 monoclonal antibody, in pediatric transplantation

Rituximab, chimeric anti-human CD-20, is approved for treatment of B-cell lymphoma in adults. It is being used experimentally in other various immune-related disease such as immune thrombocytopenic purpura, myasthenia gravis, and rheumatoid arthritis. In transplant recipients it is used for treatment of post-transplant lymphoproliferative disease, and prevention and treatment of acute rejection. There are few data on its use in children. This paper reviews the use of rituximab in these disease states and provides hypotheses for its mode of action.

Successful simultaneous pancreas kidney transplantation from living-related donor against positive cross-match

A positive pretransplant flow cytometry cross-match (FC-XM) allows precise identification of high-risk recipients vulnerable to hyperacute or accelerated rejection after transplantation. Living donor kidney transplant recipient candidates with positive cross-match have been successfully treated with a combination of plasmapheresis (therapeutic plasma exchange, TPEX) and intravenous immunoglobulin (IVIG), achieving conversion to negative cross-match and successful transplant. We report the first successful case of simultaneous pancreas kidney transplant (SPKT) from a living donor (LD) performed against an initially positive FC-XM, converted to negative using a protocol based on TPEX and IVIG in combination with antiCD20 monoclonal antibody. This strategy of overcoming the cross-match barriers in living donation may offer a chance of successful transplantation to highly sensitized candidates for SPKT, for whom cadaveric transplant is difficult to achieve.

Significance of human herpesviruses to transplant recipients

PURPOSE OF REVIEW

Despite recent great advances in transplantation techniques, herpesvirus infections remain a major cause of morbidity and mortality in transplant recipients. While improvement in immunosuppressive drug regimens have decreased the risk of graft-versus-host disease and rejection in bone marrow transplant recipients and solid organ transplant recipients, all such drugs carry with them an increased risk of herpesvirus reactivation. The following review consolidates recent findings in this field, covering reports published from January 2002 to August 2003.

RECENT FINDINGS

Real-time polymerase chain reaction has improved the ability to distinguish between latent and active herpesvirus infection, which had been a major difficulty in the diagnosis of such conditions. It has been suggested that evaluation of virus-specific cytotoxic T lymphocyte activity is important for prediction of viral diseases. Development of new antiviral drugs has provided other therapeutic options. However, neither prophylactic nor preemptive administration of antiviral drugs can completely abolish the risk of herpesvirus infection. Transfusion of virus-specific cytotoxic T lymphocytes has been suggested to be a useful treatment for recipients with continuous viral replication due to severe immunosuppression.

SUMMARY

Recent progress has been made in learning more about the role of virus-specific cytotoxic T lymphocytes, and developing better diagnostic procedures and therapeutic protocols that are efficient and have reduced adverse side effects. Reliable monitoring methods for viral load, in combination with evaluation of virus-specific cytotoxic T cells, has made possible the prediction of viral diseases and furthered understanding of the role of these cells in controlling viral infections. Furthermore, adoptive immunotherapy has been improved by analyzing host immune responses.