A recent decrease in the time to development of monomorphous and polymorphous posttransplant lymphoproliferative disorder

Posttransplant lymphoproliferative disorder in the wall of a lymphocele: a case report

Posttransplant lymphoproliferative disorder (PTLD) is a well-known complication of renal transplantation with increased incidence after introduction of more powerful immunosuppressive drugs. Presenting symptoms are nonspecific; some patients may be entirely asymptomatic. Herein we have reported a case of PTLD arising in the lymphocele wall presenting with B-symptoms and deterioration of graft function. A 62-year-old-female with end-stage renal disease secondary to Balkan endemic nephropathy and positive Epstein-Barr virus (EBV) serology before transplantation received a renal transplant from a deceased donor. Six months after transplantation she was admitted to the hospital with a 1-week history of malaise, weight loss, anorexia, night sweats, and febrile episodes. Multisliced computed tomography demonstrated a cystic structure at the renal hilus. Graft function deteriorated, so the patient underwent puncture of the lymphocele. Urgent graftectomy was necessary to stop the bleeding. Pathohistology demonstrated EBV-positive, CD20-positive PTLD. The patient received 6 cycles of chemotherapy and continued on hemodialysis. We concluded that a high index of suspicion for PTLD should be maintained when evaluating lymphoceles arising in the later posttransplantation period. Irrespective of their imaging features, biopsy should be performed to exclude PTLD.

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.

Early Posttransplant Lymphoproliferative Disease in Pediatric Liver Transplant Recipients

Among 23 pediatric patients who underwent orthotopic liver transplant (OLT), we report two (11 and 26 months old) with posttransplant lymphoproliferative disease (PTLD) that occurred in the early posttransplantation period. They were Epstein-Barr Virus (EBV)-negative and received graft from EBV-positive donors. The surveillance for EBV viremia using serial EBV polymerase chain reaction determinations in the peripheral blood was positive at 10 and 90 days after OLT concomitant with symptoms of primary infection, both patients were treated with gancyclovir. The patients should progression to a Burkitt's and a non-Hodgkin's lymphoma that appeared 3 months posttransplantation. They were treated by withdrawal of immunosuppression and six courses of cyclophosphamide as well as anti-CD20 monoclonal antibody (Rituximab) every 21 days. One patient experienced acute graft rejection, which resolved with steroids and low doses of tacrolimus, she is free of disease at 24 months after the end of treatment. The other patient relapsed with a cerebral lymphoma, receiving aggressive chemotherapy, but died due to sepsis. In conclusion, PTLD occurred among in 2/23 patients who underwent OLT and appeared in the first quarter post OLT. The risk factors associated with early PTLD were primary EBV infection after OLT, young age, and EBV-negative recipient receiving a transplant from an EBV-positive donor. Antiviral treatment alone was inefficient; withdrawal of immunosuppression and courses of Rituximab and cyclophosphamide were well tolerated and controlled PTLD. The risk of graft rejection was increased by withdrawal of immunosuppression. One patient died.

Differences between early and late posttransplant lymphoproliferative disorders in solid organ transplant patients: are they two different diseases?

BACKGROUND

The objective of the authors' study was to characterize the clinical and pathologic differences between patients who develop posttransplant lymphoproliferative disorders (PTLD) early or late after transplantation and to assess the overall survival in these two groups.

METHODS

One hundred seven adult solid organ transplant patients were identified at the Mayo Clinic between December 1970 and May 2003.

RESULTS

Forty-nine patients developed PTLD within the first year (early PTLD, 1-11.8 months) and 58 patients developed PTLD after 1 year (late PTLD, 14 months-17 years). Patients with early PTLD more commonly had the following characteristics: positive Epstein-Barr virus (EBV) in situ hybridization status (P < 0.0001), CD20-positive status (P = 0.002), and involvement of the grafted organ (P = 0.02). Overall survival did not differ between the two groups (P = 0.25). PTLD may occur in two different settings with different characteristics.

CONCLUSIONS

Early PTLD is more commonly EBV in situ hybridization-positive and CD20-positive, and more commonly involves the grafted organ.

Double-step PCR assay to quantify Epstein-Barr viral load in peripheral blood

Posttransplant lymphoproliferative disorders (PTLD) are a severe complication arising in solid organ transplant patients. A strong correlation between Epstein-Barr virus (EBV) infection, the grade and type of immunosuppression, and the development of PTLD has been recognized. This article describes the development of a double-step polymerase chain reaction (PCR) assay for the quantification of EBV-deoxyribonucleic acid (DNA) to monitor EBV infection. Screening of samples containing >/=10(3) viral genomes/10(5) peripheral blood mononuclear cells (PBMC) or 100 micro L serum by a semiquantitative PCR assay is followed by quantification of the samples containing a high number of viral genomes in a quantitative-competitive (QC)-PCR assay. Screening by semiquantitative PCR selects samples with a high number of viral genomes for use in the more labor-intensive and expensive QC-PCR assay and thus provides a handy means for quantitative DNA analysis of large numbers of samples. Our double-step PCR assay can be employed in EBV viral load measurement in PBMC and serum samples to monitor transplanted patients at risk to develop PTLD.

Current status of liver transplantation in children

There are two critical issues on opposite ends of the timeline for patients who are eligible for liver transplantation. On the one hand, the crisis in the cadaveric organ supply makes surviving to transplant ever more risky. On the other hand, patients who receive successful transplants face the consequences of long-term immunosuppression and its potentially life-threatening complications. The donor shortage is forcing difficult decisions that affect all patients who await liver transplantation. It is important to scrutinize carefully the results of all policies that govern allocation and the ethics of the solutions we advocate to ensure that no patient subgroup is being at a disadvantage. Current immunosuppression practices are being challenged by an increasing understanding of the immunologic events triggered by the allograft and the goal to free patients from consequences of a lifetime of immunosuppression. Clinicians can expect, and perhaps require, that new immunosuppressive protocols will address how the planned intervention might be expected to advance the understanding of tolerance mechanisms. As knowledge increases, clinicians can anticipate innovative new immunosuppressive proposals. Calcineurin and steroid-free induction, the use of donor-derived bone marrow infusion, recipient pretreatment, costimulatory blockade, and new antibody induction approaches are all being proposed--often in combination--for clinical trials. Researchers face additional challenges in defining endpoints if the goal is not just the short-term reduction in rejection but the minimization, and eventual discontinuation, of immunosuppressive drugs while maintaining excellent long-term graft function. How much "failure" will be accepted and how will it be defined? How will clinicians interpret liver biopsies if they begin to accept that some lymphocytic infiltrates may be beneficial mediators of the ongoing immune activation necessary for the maintenance of tolerance? How will they adjust immunosuppression practices to the dynamic processes in the immune response that maintain tolerance? Remarkable short-term successes in providing transplants for thousands of children with liver failure have brought these challenges into sharp focus. Clinicians must seek to move the life-giving science of transplantation toward a new goal: providing long lifetimes of excellent graft function with minimal toxicity from immunosuppressive drugs and the hope of freedom from immunosuppression altogether. Pediatric liver recipients, whose grafts have inherent tolerogenic potential and for whom we can anticipate decades of life after transplant, may prove to be an ideal study population to further these goals.

Malignancy after liver transplantation in patients with premalignant conditions

GOALS

Liver transplant recipients are at increased risk of developing nonhepatic malignant tumors. The aim of the current study was to evaluate the role of premalignant states, not associated with the liver disease prior to transplantation, in the development of posttransplantation malignancy.

STUDY

One hundred seventy-five patients who had undergone liver transplantation were retrospectively evaluated for the development of malignant conditions. Each of the patients who developed malignancy following transplantation was evaluated for the presence of premalignant conditions before transplantation.

RESULTS

Post-liver transplantation malignancy was identified in 13 patients (7.4%). Five patients developed non-Hodgkin lymphoma: four had posttransplantation lymphoproliferative diseases, and one had B cell lymphoma of the stomach. Eight patients developed solid tumors. In five of these patients, evidence of a premalignant state was identified: ulcerative colitis was diagnosed in 1 patient with carcinoma of the colon; colonic polyp, 1 patient with carcinoma of the colon; Barrett esophagus, 1 patient with esophageal carcinoma; Caroli disease, 1 patient with anaplastic cholangiocarcinoma; and cervical atypia, 1 patient with carcinoma of the cervix.

CONCLUSIONS

Premalignant conditions existing before transplantation, which are not associated with the primary liver disease, are major risk factors for posttransplantation malignancy. Screening for premalignant conditions should be included in pretransplantation evaluation. Liver transplant patients with evidence of a premalignant state should be followed after transplantation for detection of malignancy.

Monoclonal antibodies to elongation factor-1alpha inhibit in vitro translation in lysates of Sf21 cells

Elongation factor-1alpha (EF-1alpha) is an enzyme that is essential for protein synthesis. Although EF-1alpha offers an excellent target for the disruption of insect metabolism, agents known to interfere with EF-1alpha activity are toxic to humans. In this article, we describe the development of monoclonal antibodies (MAbs) that can disrupt the activity of insect EF-1alpha without cross-reacting with the human enzyme. MAbs were generated to EF-1alpha from Sf21 cells derived from the fall armyworm, Spodoptera frugiperda, by immunizing mice with EF-1alpha eluted from SDS-PAGE gels. The MAbs reacted with EF-1alpha in eggs and first through fifth instars of the fall armyworm in immunoblots of SDS-PAGE gels, but did not recognize EF-1alpha in human carcinoma cells and normal tissues. MAbs with the ability to recognize EF-1alpha in its native conformation, identified through immunoprecipitation experiments, were added to Sf21 cell lysates to determine whether the antibodies could inhibit incorporation of [(35)S]methionine into newly synthesized in vitro translation products. Of the four EF-1alpha-specific MAbs tested, three significantly inhibited protein synthesis when compared to the negative control antibody (P < 0.001, one-way ANOVA; followed by Dunnett's test, P < 0.05).

Post-transplant lymphoproliferative disorder in the United States: young Caucasian males are at highest risk

We have previously documented Caucasian race and cadaver donor source as risk factors for post-transplant lymphoproliferative disorder (PTLD) development in recipients registered in the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS). We analyzed data from the Scientific Registry of the United Network of Organ Sharing (UNOS) (from January 1988 to December 1999) to determine risk factors for the development of PTLD in all organ systems and its frequency, and we compared these factors to the risk factors in the most recent NAPRTCS database (1987-2000). In the UNOS database, PTLD was reported in 2365 of 205114 organ-transplant recipients (1.2%). PTLD was reported in 3% or more of all intestinal and thoracic organ recipients, but in less than 1% of other abdominal organ recipients. Recipient age < 18 years, Caucasian race and male gender were independent risk factors [Odds Ratios (OR) 2.81, 2.22 and 1.40, respectively, p = 0.0001], but not cadaver donor source. The combination of all three risk factors increased the OR to 8.78. The occurrence of PTLD showed a significant rise per year for heart-lung, kidney, kidney-pancreas and liver transplants, but decreased significantly for heart transplants (p < 0.001). Similar frequencies of PTLD were found in smaller organ-specific registries of heart, intestine, pediatric liver and pediatric kidney transplants. The PTLD incidence per year and incidence density have increased in recent years. Young Caucasian males are at highest risk for PTLD development among solid-organ-transplant recipients. The incidence of PTLD is increasing.

Intestinal transplantation before and after the introduction of sirolimus

INTRODUCTION

Small bowel transplantation has been limited by high rates of rejection and graft loss. In June 2000, we began using sirolimus, an immunosuppression agent with proven efficacy in kidney transplantation. We reviewed results among intestinal transplant recipients before and after the introduction of sirolimus.

METHODS

Thirty-one intestinal transplants were performed in 29 patients at our center between July 1998 and April 2001. All patients were followed for at least 30 days posttransplant. In the first 19 transplants (group 1), patients received tacrolimus, steroids, and antibody induction therapy (either daclizumab or OKT3). In the next 12 consecutive transplants (group 2), patients received tacrolimus, steroids, basiliximab, and sirolimus.

RESULTS

Eighteen children (7 males and 11 females, mean age 2.1+/-2.2 years) and 11 adults (9 males and 2 females, mean age 38.1+/-12.4 years) underwent transplantation. All patients survived transplantation. The overall reoperation rate was 1.7 procedures per patient in group 1 and 1.1 procedures per patient in group 2. The most common indications were abscess (n=7), planned second look (n=7), leaks/fistulas (n=6), dehiscence (n=6), obstruction (n=4), ischemic bowel (n=3), perforations (n=3), stomal complications (n=3), and graft removal (n=3). The incidence of biopsy-proven rejection in the first 30 days was 73.7% in group 1 and 16.7% in group 2 (P<0.002). Sirolimus was temporarily held or discontinued in 66.7% of patients. Actuarial 1-year graft survival was 91.7% with sirolimus and 57.9% without sirolimus (P<0.04). Actuarial 1-year patient survival was 91.7% with sirolimus and 79% without sirolimus (P=0.12).

CONCLUSIONS

An immunosuppressive regimen that includes sirolimus has improved graft survival. Furthermore, this regimen has significantly decreased the incidence of early rejection and has eliminated early graft loss caused by fulminant rejection.

RISK FACTORS FOR POSTTRANSPLANT LYMPHOPROLIFERATIVE DISORDER (PTLD) IN PEDIATRIC KIDNEY TRANSPLANTATION: A REPORT OF THE NORTH AMERICAN PEDIATRIC RENAL TRANSPLANT COOPERATIVE STUDY (NAPRTCS)1

BACKGROUND

Posttransplant lymphoproliferative disorder (PTLD) is an important complication of transplantation. The North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) database has documented 56 cases of PTLD, the largest such series to date.

METHODS

We analyzed the available longitudinal and multicenter data in the NAPRTCS database to evaluate the demographic and therapeutic risk factors and the temporal trends for PTLD in children after renal transplantation.

RESULTS

The overall incidence of PTLD was 1.2% of all patients or 298/100,000 posttransplantation years of follow-up. However, this incidence increased from 254/100,000 years between 1987 and 1991 to 395/100,000 years from 1992 onwards. In the same periods, the time to PTLD decreased from a median of 356 days (range 843048) to a median of 190 days (range 42-944). PTLD occurred with greater frequency in white children (P=0.003) and in cadaver donor transplants (P=0.019), but there was no significant predilection for gender, younger children (0-5 years), or primary diagnosis. No significant difference was found in the use of anti-T-cell antibodies or in doses of CsA, azathioprine, or prednisone at 1 month, 6 months, and 1 year. Between 1996 and 1997, 69 patients were initiated with tacrolimus. Eight cases of PTLD were identified in these recipients to date (prevalence rate 11.5%), compared with 46/4084 (1.1%) where cyclosporine was used (P<0.0001).

CONCLUSIONS

There is a trend towards increasing incidence and earlier occurrence of PTLD in the pediatric renal transplant population. White race and cadaver donor sources are risk factors not reported before. Continued monitoring of tacrolimus immunosuppression is important.

Posttransplantation lymphoproliferative disorders in pediatric patients undergoing liver transplantation

OBJECTIVES

To study the clinicopathologic and molecular genetic findings in posttransplantation lymphoproliferative disorders (PTLDs) following pediatric liver transplantation and to determine the applicability of a recently proposed consensus classification system.

DESIGN

The clinical, pathologic, and molecular genetic findings of 11 PTLDs that occurred in 10 patients are presented. These 10 patients were derived from a group of 121 pediatric patients who underwent liver transplantation at the University of California, San Francisco. The PTLDs were classified using the proposed Society for Hematopathology scheme. Clonality was determined by immunohistochemical detection of monotypic immunoglobulin or by using polymerase chain reaction-based methods to detect monoclonal immunoglobulin heavy-chain gene rearrangements. Epstein-Barr virus (EBV) was detected by immunohistochemistry, in situ hybridization, or polymerase chain reaction. Epstein-Barr virus typing and the presence of LMP1 gene deletions were also analyzed by polymerase chain reaction.

RESULTS

There were 3 early lesions, 4 polymorphic PTLDs, and 4 monomorphic PTLDs. Monoclonality was demonstrated in 8 of 9 cases assessed. Epstein-Barr virus was present in all cases; of 9 cases assessed by polymerase chain reaction, the virus was type A in 8 and type B in 1. No EBV LMP1 gene deletions were identified. The corresponding liver explants were negative for EBV in 8 cases and positive in 1 case. Greater than 3 foci of disease and monomorphic PTLD were associated with decreased actuarial survival (P <.05).

CONCLUSIONS

The prognosis of pediatric patients with PTLD is favorable for early lesions and polymorphous PTLD, particularly in patients with localized disease. Multifocal disease and monomorphic PTLD are associated with an unfavorable prognosis.

Durable remission after aggressive chemotherapy for very late post-kidney transplant lymphoproliferation: A report of 16 cases observed in a single center

PURPOSE

Posttransplant lymphoproliferative diseases (PTLDs) represent a group of potentially lethal lymphoid proliferations that may complicate the course of solid organ transplantation. Although early-onset PTLDs frequently have a favorable outcome, late-onset PTLDs behave more alike aggressive lymphoma. We report a monocentric retrospective study that focused on PTLDs occurring later than 1 year after kidney transplantation (very late-onset PTLDs) to define their incidence, clinical presentation, pathologic features, and outcome. We particularly emphasized the follow-up of patients treated with conventional chemotherapy.

PATIENTS AND METHODS

The medical histories of all patients who developed very late-onset PTLD in our institution were reviewed, and diagnostic biopsy materials were retrospectively studied.

RESULTS

Very late-onset PTLDs were diagnosed in 16 (1.1%) of 1,421 patients. Mean (+/- SD) time to tumor onset was 103.93 +/- 70.88 months. Most tumors were Epstein-Barr virus-related monomorphic large-cell PTLDs of B phenotype. Ten patients received conventional chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisone regimen). Two of them died within 2 months, two achieved partial remission, and six achieved definitive complete remission. Overall median survival time was 13 months and rose to 27 months in the treated group. The main cause of mortality was sepsis. None of the treated patients experienced rejection despite withdrawal of immunosuppressive treatment.

CONCLUSION

Despite characteristics of aggressive lymphoma, very late-onset PTLDs after renal transplantation may respond to conventional chemotherapy. However, because a high rate of infectious complications occurred, new therapeutic strategies, such as combinations of anti-CD20 monoclonal antibodies and lower doses of chemotherapy, are warranted.

Liver transplantation. The pediatric challenge

Successful liver transplantation in a child is often a hard-won victory, requiring all the combined expertise of a dedicated pediatric transplant team. This article outlines the considerable challenges still facing pediatric liver transplant physicians and surgeons. In looking to the future, where should priorities lie to enhance the success already achieved? First, solutions to the donor shortage must be sought aggressively by increasing the use of from split-liver transplants, judicious application of living-donor programs, and increasing the donation rate, perhaps by innovative means. The major immunologic barriers, to successful xenotransplantation make it unlikely that this option will be tenable in the near future. Second, current immunosuppression is nonspecific, toxic, and unable to be individually adjusted to the patient's immune response. The goal of achieving donor-specific tolerance will require new consideration of induction protocols. Developing a clinically applicable method to measure the recipient's immunoreactivity is of paramount importance, for future studies of new immunosuppressive strategies and to address the immediate concern of long-term over-immunosuppression. The inclusion of pediatric patients in new protocols will require the ongoing insistence of pediatric transplant investigators. Third, the current immunosuppressive drugs have a long-term morbidity and mortality of their own. These long-term effects are particularly important in children who may well have decades of exposure to these therapies. There is now some understanding of their long-term renal toxicity and the risk of malignancy. New drugs may obviate renal toxicity, whereas the risk of malignancy is inherent in any nonspecific immunosuppressive regimen. Although progress is being made in preventing and recognizing PTLD, this entity remains an important ongoing concern. The global effect of long-term immunosuppression on the child's growth, development, and intellectual potential is unknown. Of particular concern is the potential for neurotoxicity from the calcineurin inhibitors. Fourth, recurrent disease and new diseases, perhaps potentiated by immunosuppressive drugs, must be considered. Already the recurrence of autoimmune disease and cryptogenic cirrhosis have been documented in pediatric patients. Now, a new lesion, a nonspecific hepatitis, sometimes with positive autoimmune markers, that may progress to cirrhosis has been recognized. It is not known whether this entity is an unusual form of rejection, an unrecognized viral infection, or a response to immunosuppressive drugs themselves. Finally, pediatric transplant recipients, like any other children, must be protected and nourished physically and mentally if they are to fulfill their potential. After liver transplantation the child's growth, intellectual functioning, and psychologic adaptation may all require special attention from parents, teachers, and physicians alike. There is limited understanding of how the enormous physical intervention of a liver transplantation affects a child's cognitive and psychologic function as the child progresses through life. The persons caring for these children have the difficult responsibility of providing services to evaluate these essential measures of children's health over the long term and to intervene if necessary. Part of the transplant physician's our duty to protect and advocate for children is to fight for equal access to health care. In most of the developing world, economic pressures make it impossible to consider liver transplantation a health care priority. In the United States and in other countries with the medical infrastructure to support liver transplantation, however, health care professionals must strive to be sure that the policies governing candidacy for transplantation and allocation of organs are applied justly and uniformly to all children whose lives are threatened by liver disease. In the current regulatory climate that increasingly takes medical decisions out of the hands of physicians, pediatricians must be even more prepared to protect the unique and often complicated needs of children both before and after transplantation. Only in this way can the challenges of the present and the future be met.

Postransplant lymphoproliferative disorder localized near the allograft in renal transplantation

BACKGROUND

Posttransplant lymphoproliferative disorder (PTLD), a complication of immunosuppression, develops in approximately 1% of renal allograft recipients. Typically, PTLD is a proliferation of B-cells associated with Epstein-Barr virus (EBV) infection; it is said to be most often a systemic disease. Involvement occasionally is localized near the allograft.

METHODS

This is a retrospective analysis of all cases of PTLD in recipients of 1474 renal transplants performed at University of Alabama at Birmingham between 1993 and 1997.

RESULTS

Of 14 patients developing PTLD, 10 had disease localized near the allograft. The mean interval from transplantation to diagnosis was 221 +/- 70 days. All patients presented with renal dysfunction; an ultrasound examination revealed a hilar mass, with hydronephrosis in five and stenosis of renal vessels in eight. No patient had lymphadenopathy, according to computerized tomographic or magnetic resonance imaging findings. After reduction of immunosuppressive therapy, seven required a nephrectomy because of rejection, progressive dysfunction, or mass enlargement. Tissue recovered in four patients was consistent with PTLD; the tumors in the remaining three patients were unresectable and regressed. One patient died 1 month after a nephrectomy, and another died 4 years after surgery; neither had evidence of PTLD when they died. Three patients retain functional grafts without clinical or radiographical evidence of progression. All patients with disseminated disease died.

CONCLUSIONS

In a large cohort of renal allograft recipients, PTLD affected 1%. Disease localized near the allograft was the most common variant. For most patients with localized disease, the outcome was graft loss, and the mortality was low. Localized PTLD should be considered in the differential diagnosis of allograft dysfunction in the 1st posttransplant year.

Tamandarins A and B: new cytotoxic depsipeptides from a Brazilian ascidian of the family Didemnidae

The structures of two new, naturally occurring cytotoxic depsipeptides, tamandarins A and B (1 and 2), are presented. The tamandarins were isolated from an unidentified Brazilian marine ascidian of the family Didemnidae. The structures of the new cytotoxins were assigned by interpretation of FABMS data and by extensive 2D NMR analyses. The absolute configurations of the tamandarins were assigned by acid and alkaline hydrolysis to yield their corresponding amino acids, which were then analyzed as their Marfey derivatives. The cytotoxicity of tamandarin A (1) was evaluated against various human cancer cell lines and shown to be slightly more potent than didemnin B. A qualitative discussion of the conformation of tamandarin A (1) in solution, obtained from NMR J-value data, variable temperature experiments, and NOESY/ROESY data, is included.

High levels of Epstein-Barr virus DNA in blood of solid-organ transplant recipients and their value in predicting posttransplant lymphoproliferative disorders

Epstein-Barr virus (EBV) DNA was quantitated in peripheral blood mononuclear cells (PBMC) from 25 healthy subjects, 105 asymptomatic solid-organ transplant (SOT) recipients, and 15 SOT recipients with symptomatic EBV infections by using a newly developed quantitative-PCR technique. Patients with symptomatic EBV infections had significantly higher (P < 0.001) median EBV DNA levels than asymptomatic SOT recipients and immunocompetent individuals. In SOT recipients, the positive predictive value of EBV DNA levels of >1, 000 genome equivalents (GE)/0.5 microg of total PBMC DNA was 64.7% for symptomatic EBV infection, while the negative predictive value was 96.1%. In 19 of 32 (59.3%) asymptomatic SOT recipients, EBV DNA levels were consistently below 1,000 GE for as long as 18 months, while 10 of 32 (31.2%) patients had 1,000 to 5,000 EBV GE at least once during follow-up. In a minority of patients (3 of 32; 9.3%), >/=5,000 GE could be detected at least once during follow-up. Reduction of immunosuppressive treatment decreased EBV DNA levels by >/=1 log(10) unit in patients with symptomatic EBV infections. Quantification of EBV DNA is valuable for the diagnosis and monitoring of symptomatic EBV infections in SOT recipients.

CD3 antibody-induced IL-10 in renal allograft recipients: an in vivo and in vitro analysis

BACKGROUND

The first administration of CD3 monoclonal antibodies, such as anti-human CD3 (OKT3), induces a massive release of several cytokines, including tumor necrosis factor alpha (TNF-alpha), interferon (IFN)-gamma, interleukin (IL)-2, IL-3, IL-6, and granulocyte-macrophage colony-stimulating factor.

METHODS

Cytokine levels in patient's sera were measured by specific ELISA. In vitro cultures were performed using OKT3-stimulated peripheral blood mononuclear cells and/or whole blood from patients and normal controls.

RESULTS

Here we describe that OKT3 administration to human renal allograft recipients also leads to a significant release of IL-10. Contrasting with most OKT3-induced cytokines, such as TNF-alpha whose release is transient, IL-10 levels show a more progressive increase, they peak only by 4-8 hr after the first OKT3 injection and persist longer. Thus, significant IL-10 levels are still detectable at the time of the second and the third OKT3 injection. Administration of corticosteroids, 1 hr before the first OKT3 injection, significantly reduced both TNF-alpha and IL-10 release. Experiments were performed to evaluate the source(s) of IL-10 and its (their) influence on the initial T-cell activation. When stimulated in culture with soluble OKT3, the production of IL-10 was dependent on the cooperation between T lymphocytes and monocytes. It is important that, as assessed through the use of a specific neutralizing antibody, the endogenous IL-10 produced in the co-culture system exerted a negative feed-back on the release of the other pro-inflammatory CD3-induced cytokines, which was reproducible.

CONCLUSION

These results are supportive of a major role of IL-10 in the down-modulation of the OKT3-triggered T-cell activation cascade.

Preventing acute rejection, Epstein-Barr virus infection, and posttransplant lymphoproliferative disorders after kidney transplantation: use of aciclovir and mycophenolate mofetil in a steroid-free immunosuppressive protocol

BACKGROUND

A widely held view is that any increase in the potency of an immunosuppressive agent will lead to an increase in infection and malignancy, such as life-threatening Epstein-Barr virus (EBV) induced posttransplant lymphoproliferative disorders (PTLD). We tested this paradigm by studying the effect of adding mofetil to a steroid-free protocol under cover of high-dose aciclovir prophylaxis on the number of acute rejections, EBV infections and PTLDs after kidney transplantation.

METHODS

EBV serology was performed in 267 consecutive renal transplantations (1990-1997). All were treated with cyclosporine with an initial 10-day antilymphocyte globulin course, supplemented from September 1995 with MMF. In 208 consecutive transplantations after June 1992 aciclovir 3200 mg/day was given for 3 months posttransplantation.

RESULTS

After an observation period of up to 7 years we found that: (1) primary or reactivated EBV infection (PREBV) was correlated to acute rejection (treated with OKT3; P<0.00005) and to the incidence of PTLD (P=0.03; P=0.01, if Hodgkin's disease is included); (2) aciclovir protected against PREBV (P<0.00005) and (3) adding mofetil to the immunosuppressive protocol reduced PREBV further (P=0.0001), (4) in 78 transplantations treated with cyclosporine/antilymphocyte globulin/mofetil we observed only 10 acute rejections (P=0.0001), 10 PREBVs (P<0.00005), and no PTLDs compared with the cyclosporine/antilymphocyte globulin group (P=0.04).

CONCLUSIONS

Supplemental immunosuppression with mofetil protects against acute rejection. In combination with aciclovir, there is also a reduction in the number of PREBVs, apparently as a result of both direct viral prophylaxis and better rejection control, and in the incidence of EBV-induced PTLD.

Posttransplantation lymphoproliferative disorder in liver recipients: characteristics, management, and outcome

Posttransplantation lymphoproliferative disorder (PTLD) is a well-recognized complication of organ transplantation. The aim of this study, performed over 9 years, was to examine the histopathological findings, clinical course, and outcome of patients who, having undergone orthotopic liver transplantation (OLT), developed PTLD. The sample included 7 adult liver allograft recipients (1.7%), 4 men and 3 women, with a mean age of 53 years (range, 40 to 61 years) who developed PTLD 1 to 36 months post-OLT (mean, 6 months). Four patients received either antithymocyte globulin as primary immunosuppression or OKT3 for steroid-resistant cellular rejection. Four patients had localized hepatic tumor with or without regional lymph node involvement, 2 patients had extralymphoreticular disease (head of pancreas and chest wall), and 1 patient had spleen and lymph node involvement. All tumors were B-cell lymphomas; three polymorphic and four monomorphic. Clonality was assessed by immunostaining for kappa and lambda and gene rearrangement. Monoclonality was found in 4 patients and polyclonality in 2 (1 of whom progressed to monoclonality); in 2 patients, clonality could not be determined. Immunohistochemistry findings for the presence of the Epstein-Barr virus (EBV)-determined nuclear antigen and the latent membrane protein 1 were noted in lymphoma tissue in 6 patients. Immunosuppressive therapy was decreased in all patients. Polyclonal tumors were treated with acyclovir (1 patient is in complete remission and 1 patient died), and monoclonal tumors with systemic chemotherapy (2 patients are in complete remission and 2 patients died). One patient was treated with monoclonal antibodies (CD20) but failed to respond, and 1 patient was treated with excision and is in complete remission. The mortality rate was 43%; for the remainder, median survival is 21 months (range, 10 to 42 months). We conclude that PTLD may re-present early after OLT. EBV has a special role in the pathogenesis, combined with immunosuppressive therapy. The outcome is poor, and new therapeutic approaches are needed.

Prevention and preemptive therapy of postransplant lymphoproliferative disease in pediatric liver recipients

BACKGROUND

We have previously reported a 10% incidence of posttransplant lymphoproliferative disease (PTLD) in pediatric patients receiving first liver grafts and primarily immunosuppressed with tacrolimus. To decrease the incidence of PTLD, we developed a protocol utilizing preemptive intravenous ganciclovir in high-risk recipients (i.e., donor (D)+, recipient (R)-), combined with serial monitoring of peripheral blood for Epstein Barr virus (EBV) by polymerase chain reaction (PCR).

METHODS

Consecutive pediatric recipients of a first liver graft were immunosuppressed with oral tacrolimus (both induction and maintenance), and low-dose prednisone. EBV serologies were obtained at the time of orthotopic liver transplant in recipients and donors. Recipients were divided into groups: group 1, high-risk (D+R-), and group 2, low-risk (D+R+; D-R-; D-R+). In group 1 (high-risk), all patients received a minimum of 100 days of intravenous ganciclovir (6-10 mg/kg/day), while, in group 2 (low-risk), patients received intravenous ganciclovir during their initial hospitalization and then were converted to oral acyclovir (40 mg/kg/day) at discharge. Semiquantitative EBV-PCR determinations were made at 1-2-month intervals. In both groups, patients with an increasing viral copy number by EBV-PCR had tacrolimus levels decreased to 2-5 ng/ml. Tacrolimus was stopped, and intravenous ganciclovir reinstituted for PTLD. A positive EBV-PCR with symptoms, but negative histology, was defined as EBV disease; PTLD was defined as histologic evidence of polyclonal or monoclonal B cell proliferation.

RESULTS

Forty children who had survived greater than 2 months were enrolled. There were 18 children in group 1 (high-risk; mean age of 14+/-15 months and mean follow-up time of 243+/-149 days) and 22 children in group 2 (low-risk; mean age of 64+/-65 months and follow-up time of 275+/-130 days). In group 1 (high-risk), there was no PTLD and one case of EBV disease (mononucleosis-like syndrome), which resolved. In group 2 (low-risk), there were two cases of PTLD; both resolved when tacrolimus was stopped. Both children were 8 months old at time of transplant. Neither received OKT3, and they had one and two episodes of steroid-sensitive rejection, respectively. One child had EBV disease (mild hepatitis), which resolved.

CONCLUSIONS

Since instituting this protocol, the overall incidence of PTLD has fallen from 10% to 5% for children receiving primary tacrolimus therapy after OLT. No high-risk pediatric liver recipient treated preemptively with intravenous ganciclovir developed PTLD. Both children with PTLD were less than 1 year at OLT and considered low-risk. However, their positive EBV antibody titers may have been maternal in origin and not have offered long-term protection. Serial monitoring of EBV-PCR after pediatric OLT is recommended to decrease the risk of PTLD by allowing early detection of EBV infection, which is then managed by decreasing immunosuppression and continuing intravenous ganciclovir.

Combined radiation and chemotherapy in posttransplant lymphoproliferative disorder

The optimal treatment for posttransplant lymphoproliferative disorder which has progressed despite a reduction in immunosuppression has not been defined. We report on two patients with stage I posttransplant lymphoproliferative disorder who developed progressive disease despite a reduction in the level of immunosuppression. Both patients were treated with combined short course CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy followed by involved-field radiation therapy. In both patients, a rapid response was obtained followed by complete remission. Combined modality therapy can be utilized successfully in progressive limited stage posttransplant lymphoproliferative disorder.

An antibody diagnostic for hymenopteran parasitism is specific for a homologue of elongation factor-1 alpha

An enzyme-linked immunosorbent assay (ELISA) useful for identifying noctuid pests parasitized by hymenopteran endoparasitoids was recently described. The ELISA employed a monoclonal antibody (MAb 9A5) that appeared highly polyspecific for parasitoid antigens, yielding banding patterns more typical of a polyclonal antiserum than of a monoclonal antibody in immunoblots of parasitoid homogenates subjected to SDS-PAGE. Although MAb 9A5 appeared capable of binding to dozens of parasitoid antigens, no cross-reactivity for noctuid antigens was evident by either immunoblotting or ELISA. In the study described here, immunoprecipitation, SDS-PAGE, and N-terminus amino acid sequencing were used to identify the protein recognized by MAb 9A5 as a homologue of elongation factor-1 alpha (EF-1 alpha). The propensity for EF-1 alpha to bind to cytoskeletal components, the additional subunits of EF-1, and other proteins may account for the apparent polyspecificity of MAb 9A5 in immunoblots of whole-body parasitoid homogenates. The presence of a unique hymenopteran epitope suggests that EF-1 alpha molecules from other insect groups could similarly express novel determinants. These determinants may prove useful not only for insect detection, but also as targets for selective insecticides that act by inhibiting protein synthesis.

Durable remission after aggressive chemotherapy for post-cardiac transplant lymphoproliferation

A frequently fatal complication of organ transplantation, post-transplant lymphoproliferative disorder (PTLD) develops in 2%-6% of cardiac recipients. Treatment remains poorly defined. Reduction in immunosuppression is effective in a proportion of cases, but mortality in the order of 80% is reported for patients requiring chemotherapy. The reason for such poor outcomes is unclear, but may be partly due to the concomitant use of immunosuppressives. An update report is provided on nineteen consecutive cardiac recipients with PTLD, studied retrospectively in terms of clinical features and outcome. Patients were managed according to a uniform treatment approach. Initial therapy was a trial of reduced immunosuppression with concomitant acyclovir followed, if unsuccessful, by aggressive combination chemotherapy. The regimen used was predominantly ProMACE-CytaBOM. Six patients with phenotypically polyclonal PTLD presented <6 months after transplantation (median 6 weeks). Only 1/4 (25%) treated patients responded to reduced immunosuppression; the remainder died of multiorgan failure. Thirteen patients presented with phenotypically monoclonal disease > or =6 months after transplantation. In 8/12 (75%) treated patients initial therapy was reduction in immunosuppression. None achieved CR; 2 experienced fatal rejection. Two patients achieved durable surgical CR. The remaining 8 patients received chemotherapy; 2/8 (25%) died during treatment, 6/8 (75%) achieved CR. None have relapsed, at a median duration of follow-up of 64 months. Neutropenic sepsis, and subclinical doxorubicin cardiotoxicity at a mean cumulative dose of 63 mg/m2 were the principal toxicities. Our data indicate that aggressive chemotherapy is feasible and can produce very durable remissions in phenotypically monoclonal PTLD refractory to reduced immunosuppression. ProMACE-CytaBOM is well suited to cardiac recipients, minimizing doxorubicin exposure and obviating the need for concurrent immunosuppressives.

A prospective study in heart and lung transplant recipients correlating persistent Epstein-Barr virus infection with clinical events

BACKGROUND

A 2-year prospective study was set up with 30 cardiothoracic transplant recipients to study Epstein-Barr virus (EBV) infection and immunity and their correlation with clinical events.

METHODS

Regression assays were used to measure EBV-specific cytotoxic T lymphocyte (CTL) function. Tissue culture, immunoblotting, and polymerase chain reaction were used for EBV detection and isolate variation studies.

RESULTS

CTL activity was significantly lower in pretransplant seropositive patients than in healthy controls (P<0.001). CTL response was undetectable in all patients during the first 6 months after transplantation, but returned at levels significantly lower than pretransplant and control levels during the second posttransplant year (P<0.001). Return of CTL function was directly correlated with time of last treated rejection episode (P<0.003) and duration of high plasma levels of cyclosporine (over 400 ng/ml; P<0.003). Significantly higher levels of EBV were detected in peripheral blood during the first 6 months than in pretransplant or control samples (P<0.05). Excretion of EBV in throat washings was significantly lower during the first 3 months when all patients were receiving acyclovir than in pretransplant and control samples (P=0.02). An increase in virus shedding was noted 3-6 months after transplantation, which was significantly higher than in pretransplant patients and controls (P<0.05). Comparison of recipients' and donors' virus isolates in 11 cases showed that seropositive recipients retained their original EBV isolate and did not acquire the donor virus.

CONCLUSIONS

Immunosuppression decreased EBV-specific host immune function, which in turn favored increased EBV load in peripheral blood and increased excretion in the oropharynx. The transfer of donor virus to the seropositive recipients was not observed.

Kidney allograft with a lymphocytic infiltrate: acute rejection, posttransplantation lymphoproliferative disorder, neither, or both entities?

The two cases presented illustrate the diagnostic difficulties and recommend an approach to use in patients in whom features of acute renal allograft rejection and posttransplant lymphoproliferative disorder (PTLD) appear simultaneously in allograft biopsies. Both patients developed acute allograft rejection episodes in the early post-transplant period followed by severe immunosuppression (OKT-3) and active Epstein-Barr virus infection. In addition to early recognition of light microscopic features of PTLD, immunohistology and in situ hybridization for EBV complement the diagnostic work-up and provide clues to the prompt diagnosis of rapidly developing PTLD affecting the allograft even in the face of persisting rejection.

Epstein-Barr virus lymphoproliferative disorders after liver transplantation

Post-transplant lymphoproliferative disorders (PTLD) represent a spectrum of histological and immunological abnormalities, ranging from benign polyclonal B-cell hyperplasia to monoclonal malignant lymphoma. The important role of Epstein-Barr virus (EBV) in PTLD in liver transplant patients, particularly in pediatric recipients, is reviewed. Understanding the risks of EBV infection, the clinical presentations and diagnosis of PTLD, and its pathophysiology are crucial to the management of these disorders. Current treatment methods have resulted in better outcomes of these disorders, which in the past were uniformly fatal.

Analysis of Epstein-Barr virus-associated posttransplantation lymphoproliferative disorder after lung transplantation

BACKGROUND

Epstein-Barr virus (EBV)-associated posttransplantation lymphoproliferative disorder (PTLD) is a serious complication of lung transplantation. Besides immunosuppression the risk factors for PTLD development are largely unknown.

METHODS

The incidence of PTLD was ascertained in a lung transplant population consisting of 45 patients. Nine patients (20%) experienced PTLD. The clinical, histologic, and human leukocyte antigen (HLA) data were collected on all patients. The incidence of EBV infection in lymphoid tissue taken at the time of engraftment was studied by using EBV in situ hybridization.

RESULTS

All patients with PTLD had polymorphous lymphoproliferations, seven of which were polymorphous B-cell hyperplasias and two of which were polymorphous B-cell lymphomas. EBV was identified in all lesions. All patients with polymorphous B-cell hyperplasias had clinically unsuspected disease, five of which were identified at autopsy. The two polymorphous B-cell lymphoma lesions were monoclonal and regressed with immunosuppression reduction. EBV in situ hybridization on donor or recipient lymph nodes obtained at engraftment from the 45 transplant recipients showed no difference in the number of EBV positive cells in patients with and without PTLD. Cyclosporine and PTLD and azathioprine dosages and cyclosporine levels were similar between patients with and without PTLD. PTLD was seen in patients with high cumulative doses of antilymphocyte globulin. Analysis of HLA status showed a predominance of HLA A2 and DR7 in the donors of the patients with PTLD, whereas donor HLA B7 was more common in patients without PTLD>

CONCLUSIONS

Detailed studies are necessary to further elucidate the risk factors for PTLD development in the lung transplant population.

Synthetic Routes to a Constrained Ring Analog of Didemnin B

The didemnin class of biologically active cyclodepsipeptides, isolated from a marine tunicate, has shown antitumor, antiviral, and immunosuppressive activities. Synthetic studies were undertaken to prepare a modified analog of one of the most potent congeners, didemnin B (1). The side chain of the isostatine unit was tethered into the macrocycle viaa cyclohexane ring in order to provide a more rigid conformation and determine the importance of this unit in bioactive compounds. This modification created a new macrocycle core and generated a diastereomeric mixture of a constrained analog of didemnin B (2).

Clinical use of tacrolimus (FK-506) in infants and children with renal transplants

Although cyclosporine (CsA)-based immunosuppressive regimens have been highly successful in renal transplantation in infants and children, their adverse influence on somatic growth, general appearance, and blood pressure are of particular importance in this population. Over the past 4 years, we have utilized tacrolimus (formerly FK-506) as the primary immunosuppressive agent in 43 unselected children and achieved 1-year and 3-year allograft survival rates of 96% and 85%, respectively. We have also used tacrolimus to rescue 14 of 19 (74%) renal allografts from CsA-resistant rejection. Corticosteroids were discontinued in 62% of non-rescue patients without increasing the risk of rejection or renal dysfunction over a mean follow-up time of 25 months. Tacrolimus monotherapy has been associated with improved body growth and less obesity, while tacrolimus alone or in combination with prednisone was virtually free of hirsutism or gingival hypertrophy, and posed a low risk for hypertension. A major disadvantage of this regimen may be an increased risk for viral infections and a benign form of posttransplant lymphoproliferative disease. This article describes the tacrolimus protocol utilized in our center and focuses on practical clinical issues including therapeutic monitoring, benefits, and major toxicity in children with renal allografts.