Significance of Epstein–Barr virus status and post‐transplant lymphoproliferative disease in pediatric thoracic transplantation

Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disease (PTLD) is a serious complication of organ and bone marrow transplantation. The importance of EBV matching between recipient and donor remains unclear. Between October 1987 and December 1997, 64 pediatric cardio-pulmonary transplants were performed at this center (58 hearts, two heart/lungs, four sequential single lungs). The EBV viral capsid antigen (VCA) immunoglobulin G (IgG) status of both donor and recipient was determined at the time of transplant. Of 56 patients from whom paired sera was available for analysis, 27 (50%) were recipient and donor EBV IgG positive, four (7%) were recipient EBV IgG positive and donor EBV IgG negative, and 12 (20%) were recipient EBV IgG negative and donor EBV IgG negative. The remaining 13 (23%) patients were EBV IgG negative but received organs from EBV IgG-positive donors. The EBV immunoglobulin M (IgM) status was determined from 6 weeks post-transplant in the 11 mismatches who survived for longer than 28 d. Seven became EBV IgM positive, two remained EBV IgM negative; the status of the remaining two remains unknown. The EBV IgM status was also determined retrospectively in patients who were EBV IgG negative pretransplant and received organs from EBV IgG-negative donors. Nine became EBV IgM positive; the rest remained negative. PTLD was diagnosed in two of 56 patients from whom paired sera was available; one was donor and recipient EBV IgG negative; the other was donor and recipient EBV IgG positive. No cases of PTLD were diagnosed in the remaining eight patients from whom paired sera was not available. Our experience suggests that PTLD does not occur with any greater frequency in the 'mismatch' group, and does not justify EBV matching in pediatric thoracic transplantation where there is a higher proportion of EBV-negative recipients than in adults.     

Native kidney post-transplant lymphoproliferative disorder in a non-renal transplant patient

Abstract:  PTLD is an important post-transplant complication. Although PTLD affects kidney allografts after renal transplantation, it has not been reported in native kidneys of other solid organ recipients. Herein, we report a child who underwent an orthotropic liver transplant for cryptogenic cholestatic hepatitis and developed fever, generalized lymphadenopathy, chronic EBV viremia, and lymphatic PTLD. Subsequently, she also developed gross hematuria and nephrotic range proteinuria. Kidney histology revealed EBV-positive mononuclear infiltrates within the renal parenchyma consistent with PTLD. Electron microscopy examination demonstrated subepithelial electron-dense deposits consistent with a membranous glomerulopathy pattern. The PTLD was successfully treated with reduced immunosuppression and cyclic cyclophosphamide, rituximab, and prednisone, but the renal disease progressed to end-stage renal failure within two yr. Repeat kidney histology showed chronic nephropathy and membranous glomerulopathy without PTLD infiltrates or detectable EBV staining, although chronic viremia persisted. To our knowledge, this is the first such child to be reported and highlights the importance of remaining vigilant for renal PTLD even in non-kidney organ recipients.     

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.     

Emerging therapeutic strategies for Epstein-Barr virus+ post-transplant lymphoproliferative disorder

De novo malignancies represent an increasing concern in the transplant population, particularly as long-term graft and patient survival improves. EBV-associated B-cell lymphoma in the setting of PTLD is the leading malignancy in children following solid organ transplantation. Therapeutic strategies can be categorized as pharmacologic, biologic, and cell-based but the variable efficacy of these approaches and the complexity of PTLD suggest that new treatment options are warranted. Here, we review current therapeutic strategies for treatment of PTLD. We also describe the life cycle of EBV, addressing the viral mechanisms that contribute to the genesis and persistence of EBV+ B-cell lymphomas. Specifically, we focus on the oncogenic signaling pathways activated by the EBV LMP1 and LMP2a to understand the underlying mechanisms and mediators of lymphomagenesis with the goal of identifying novel, rational therapeutic targets for the treatment of EBV-associated malignancies.     

Complete immunosuppressive withdrawal as a uniform approach to post-transplant lymphoproliferative disease in pediatric liver transplantation

Epstein–Barr virus (EBV)‐associated post‐transplant lymphoproliferative disease (PTLD) in pediatric liver transplant recipients is associated with a high mortality (up to 60%) and the younger age groups, who are predominantly EBV‐naïve, are at highest risk for development of this disease. The aim of this study is to assess, in this high‐risk group, patient outcome and graft loss to rejection when complete withdrawal of immunosuppressive agents (IMS) is instituted as the mainstay of treatment in addition to the use of standard therapy. A retrospective analysis of 335 pediatric patients whose liver transplants were performed by our team between September 1988 and September 2002, was carried out through review of computer records, database and patient charts. Fifty patients developed either EBV or PTLD; 80% were ≤2 yr of age. Of these 50 patients, 19 had a positive tissue diagnosis for PTLD and 31 were diagnosed with EBV infection, 14 of whom had positive tissue for EBV. Fifty‐eight percent of patients who developed PTLD and 51.6% of patients with EBV received antibody for induction or treatment of rejection prior to onset of disease. Forty‐six patients (92%) received post‐transplant antiviral prophylaxis with ganciclovir or acyclovir. Antiviral treatment included ganciclovir in 76%, acyclovir in 20% and Cytogam (in addition to one of the former agents) in 44%. In those with PTLD, treatment included chemotherapy (n = 1), Rituximab (n = 2), and ocular radiation (n = 1). IMS was stopped in all patients with PTLD and in 19 with EBV infection and was held as long as there was no allograft rejection. Eight patients have remained off IMS for a mean of 1535.5 ± 623 days. Of the 21 patients who were restarted on IMS for acute rejection, 18 responded to steroids and/or reinstitution of low‐dose calcineurin inhibitors. The mean time to rejection while off IMS in this group was 107.43 ± 140 days (range: 7–476). Two patients were re‐transplanted for chronic rejection; one had chronic rejection that existed prior to discontinuing IMS. The mortality rate in our series was 31.6% in those with PTLD and 6% in those with EBV disease. The cause of death was related to PTLD or sepsis in all cases; no deaths were due to graft loss from acute or chronic rejection. PTLD is associated with high mortality in the pediatric population. Based on this report, we advocate aggressive management of PTLD that is composed of early cessation of IMS, the use of antiviral therapy, and chemotherapy when indicated. Episodes of rejection that occur after stopping IMS can be successfully treated with standard therapy without graft loss to acute rejection.     

Serial detection of Epstein-Barr virus DNA in sera and peripheral blood leukocyte samples of pediatric renal allograft recipients with persistent mononucleosis-like symptoms defines patients at risk to develop post-transplant lymphoproliferative disease

We tested blood samples of 25 pediatric renal transplant recipients for Epstein-Barr virus (EBV) DNA load by quantitative polymerase chain reaction (PCR). Eleven of these transplant recipients showed clinical persistent mononucleosis-like symptoms years after transplantation (Tx). A quantitation of EBV DNA by PCR in peripheral blood lymphocyte (PBL) and serum samples revealed variable EBV DNA titers. The majority of EBV PCR results in samples of the 14 asymptomatic transplant recipients was repeatedly below detection limit. In contrast, patients with mononucleosis-like symptoms showed persistent EBV genome titers over a period of 6 months, ranging from 75 to 18 750 copies/10 000 PBL and from 680 to 335 000 copies/mL serum, respectively. One child suffering from this mononucleosis-like condition developed an EBV-associated Burkitt-like lymphoma 29 months after Tx. Whereas clinical and histological investigations did not indicate a post-transplant lymphoproliferative disorder (PTLD) until tumor detection, EBV titers in PBL and serum had been high for at least 8 months. We propose that pediatric transplant recipients who show both, recurrent mononucleosis-like symptoms and a sustained high EBV genome load, are at increased risk for severe EBV-related post-transplant complications.     

Monitoring and modulation of Epstein-Barr virus loads in pediatric transplant patients

A major risk faced by bone-marrow and solid organ transplant patients is the development of post-transplant lymphoproliferative disease or post-transplant lymphoma (PTLD). In pediatric transplantation, PTLD onset is often associated with a rapid rise in Epstein-Barr virus (EBV) load in peripheral blood mononuclear cells (PBMC). We have analyzed EBV viral loads in PBMC over time using real-time quantitative PCR in 56 patients, 19 of which have been followed for more than 1 year. In nine patients; eight bone marrow (BMT) and one kidney transplant, PTLD was associated with a rapid rise in viral load, exceeding 1 x 10(5) EBV genomes/microg of PBMC-derived DNA. Four of these patients exceeded 1 x 10(6) EBV genomes/microg PBMC DNA. All patients with viral loads exceeding 1 x 10(5) EBV genomes/microg PBMC DNA were clearly at high risk for transplant-associated mortality, with only six of nine surviving. Importantly, only one of these deaths was directly attributable to EBV. A second elevated state of EBV load, defined as exceeding 2 x 10(4) EBV genomes/microg PBMC, was seen in a total of 12 BMT, kidney, heart, and liver transplant patients. These patients did not appear to be at immediate lethal risk for PTLD and one EBV-attributable death was found in this group as well. Thirty-four transplant patients whose EBV viral load oscillated from undetectable to 10 000 EBV genomes/microg PBMC DNA are reported as well. The threshold for normal EBV viral load based on our combined experience with viral load analysis is defined as 1 x 10(4) EBV genomes/microg PBMC DNA. The ability to rapidly analyze EBV load allows rapid changes in viral load, such as those that occur with PTLD onset, and the impact of anti-CD20 antibody therapy to be rapidly detected.     

Monitoring of Epstein–Barr virus load and antibody in pediatric renal transplant patients

Background: Epstein–Barr virus (EBV) infection can lead to life-threatening post-transplant lymphoproliferative disorder (PTLD). The aim of the present study was to establish EBV monitoring methods to prevent PTLD.
Methods: EBV-DNA load was investigated, using real-time polymerase chain reaction (PCR) and anti-EBV antibody titers, in peripheral blood mononuclear cells of 21 renal transplant patients (seven recipients who were EBV-seronegative, R[−]; 14 who were EBV-seropositive, R[+]) before grafting. The mean age at entry and the mean follow-up period was 7.8 years of age (range, 3.3–12.0 years) and 1.8 years (range, 0.4–4.0 years), respectively, in the R(−) group, and 12.5 years of age (range, 3.9–17.7 years) and 3.8 years (range, 0.8–8.2 years) in the R(+) group, respectively.
Results: The mean maximum load of the EBV genome was 1071 copies/μg DNA (range, 106–20700 copies/μg DNA) in the R(−) group, and 61 copies/μg DNA (range, <50–552 copies/μg DNA) in the R(+) group. During follow up no patient in the R(+) group had any noticeable symptoms that could be related to EBV, but three recipients in the R(−) group developed EBV-related symptoms including adenoid hypertrophy, cervical lymphadenopathy, and PTLD (B cell lymphoma), in one patient each. In the R(−) group the first leukocyte-associated viremia was detected at 30–180 days, and seroconversion at 43–266 days after transplantation.
Conclusions: Viral DNA detection using PCR is a useful tool for EBV surveillance, but the maximum EBV load was not markedly elevated (2474 copies/μg DNA) in a patient with PTLD. Therefore, EBV surveillance using only monitoring of EBV load in peripheral leukocyte may be insufficient. Histology may therefore be necessary to accurately diagnose PTLD.     

Asymptomatic high Epstein-Barr viral load carriage in pediatric renal transplant recipients

High viral load carriage of EBV is one of the risks for PTLD in transplant recipients. We reviewed retrospectively in pediatric renal transplant recipients with EBV seronegative. EBV loads in peripheral blood and EBV-CTLs were measured every 1-3 months in 13 patients after grafting. Immunosuppressants were reduced when the patients were considered to have persistent high EBV loads (>1000 copies/μgDNA for over six months). All showed primary EBV infection: six with asymptomatic persistent high EBV loads (group A) and seven with neither EBV-associated symptoms nor persistent high EBV loads (group B). No patient developed PTLD in either group. Chronic rejection occurred in one patient in group A after immunosuppressants' reduction. There was no difference in renal dysfunction rates between the two groups. The maximum and increase rates in EBV loads were significantly higher in group A. The CTLs' percentage was significantly lower in group A when EBV loads first rose above 100 copies/μg DNA. This study suggests the possibility that EBV loads and CTLs' monitoring may be useful for avoidance of PTLD, as patients with asymptomatic persistent high EBV loads had higher EBV loads and lower percentages of CTLs.     

Sirolimus for pediatric liver transplant recipients with post-transplant lymphoproliferative disease and hepatoblastoma

Sirolimus is a promising immune suppressive agent, with the potential to reduce calcineurin inhibitor associated nephrotoxicity, halt progression of chronic rejection and prevent tumor proliferation. The aim of this study was to review the experience using sirolimus in pediatric liver transplant recipients at a single center. Database and medical charts of all pediatric liver transplant recipients receiving sirolimus at the Hospital for Sick Children in Toronto were reviewed. Eight patients received sirolimus between October, 2000 and September, 2002. Indications for using sirolimus were post-transplant lymphoproliferative disease (PTLD) (n = 6) and hepatoblastoma (n = 2). Two patients with PTLD concurrently had renal impairment and chronic rejection. Sirolimus dosages ranged between 1.5 and 5 mg once daily. Median duration of follow-up was 17 months. Persistently elevated liver transaminase levels in the two children with chronic rejection decreased during sirolimus therapy. Recurrence of PTLD occurred in one patient. Two patients were diagnosed with acute cellular rejection after transition to maintenance sirolimus monotherapy. Resolution of adverse effects including mouth sores (n = 3), leg swelling (n = 2) and hyperlipidemia (n = 3) occurred either spontaneously or with dose reduction. Sirolimus was discontinued in four patients because of persisting bone marrow suppression, interstitial pneumonitis, life-threatening sepsis and refractory diarrhea. Children with PTLD or hepatoblastoma may benefit from immune suppression with sirolimus after liver transplantation. Further multi-center, prospective, randomized controlled trials will be instrumental to further the knowledge of long-term efficacy, safety and tolerability of sirolimus for selected children following liver transplantation.     

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.     

Unusual presentation of graft‐versus‐host disease in pediatric liver transplant recipients: Evidence of late and recurrent disease

Graft-versus-host disease (GvHD) is a multi-organ disease caused by mature donor T cells that are activated by alloantigens expressed by the host antigen-presenting cells. GvHD has been reported after solid organ transplantation with two principal presentations: humoral and cellular. In the cellular type of GvHD after liver transplantation the symptoms are identical to the GvHD after bone marrow transplant, except that the liver is spared because it lacks host antigens. We have described three cases of intestinal GvHD after pediatric liver transplant with an unusual recurrent late presentation in two patients. Two patients were female, and their age at the time of transplant was 8 and 9 months, respectively, and one was an 8-month-old male. They all received reduced liver allografts of identical blood type from three different donors. One patient received two doses of donor bone marrow cell infusion. Two patients received double immunosuppressive therapy constituted by tacrolimus at a dose of 0.05 mg/kg p.o. b.i.d. and steroids 10 mg p.o. daily. One patient received a triple drug immunosuppression with tacrolimus (0.05 mg/kg p.o. b.i.d.), steroids (10 mg p.o. daily) and mycophenolate mofetil (125 mg p.o. b.i.d.). Diagnosis of intestinal GvHD was confirmed histologically on intestinal biopsies performed at the time of presentation of the clinical symptoms or at autopsy.     

Epstein-Barr virus DNA load and seroconversion in pediatric renal transplantation with tacrolimus immunosuppression

EBV infection is one of major complications arising in pediatric patients who have undergone renal transplantation. A strong correlation between the grade of immunosuppression and the development of PTLD, one of the most severe EBV-associated diseases, has been recognized. In this study, we monitored the serologic profile in conjunction with peripheral blood EBV-DNA load of 32 children who underwent renal transplantation with tacrolimus as an immunosuppressant. Six patients were EBV-seronegative (EBV-) before the transplantation, and the mean DNA load in the EBV- group was significantly higher than that in the EBV-seropositive (EBV+) group. Seroconversion occurred in five of these patients in a mean period of 22 weeks after the transplantation. The EBV-DNA load in the EBV+ group was maintained at a low level for a year, whereas it increased rapidly to over 1 x 10(5) copies/mL in two patients in the EBV- group three to seven months after the transplantation, which corresponds to the timing of seroconversion, and one of them developed PTLD. These observations suggest that the close monitoring of the EBV-DNA load, along with longitudinal observation of seroconversion, is essential in pediatric renal transplantation, particularly for younger children who are more likely to be EVB-.     

Diagnosis and treatment of post-transplantation lymphoproliferative disorder in pediatric heart transplant patients

PTLD is a severe complication in transplant recipients. Detection of increased EBV load in the peripheral blood acts as a surrogate marker for increased risk of PTLD development. We analyzed the time course of the disease, its severity, the organs involved, and mortality rates in our institutional experience of pediatric heart transplantation. This paper identifies risk factors for PTLD and describes the different ways of diagnosing and treating the disease. PTLD was screened for in 146 pediatric heart transplant patients using a retrospective analysis in patients who received transplantation before 1998. Prospective determination was performed in 72/146 patients transplanted after 1998 within the post-transplant follow-up. The occurrence of PTLD with all interventions, including tapering of immunosuppression, surgery, viral monitoring, and antiviral interventions, was recorded. PTLD was diagnosed in 12/147 (8.2%) children at a mean age of 7.2 +/- 3.3 yr after a mean post-transplant period of 3.2 +/- 2.2 yr. PTLD manifested in: lymph nodes (n = 4), intestine (n = 3), tonsils and adenoids (n = 2), eye (n = 2), and lung (n = 1). It was diagnosed in 7/12 as a monomorphic B-cell lymphoma and in four patients as a monomorphic Burkitt lymphoma, a polymorphic B-cell lymphoma, a T-cell rich or angiocentric lymphoma (Liebow) and as reactive plasmacytic hyperplasia (early lesion), respectively. Histology was not possible in one patient with ocular manifestation. EBV association was 83%. Risk factors in the comparison with patients without PTLD were age at time of Tx, primary EBV infection after Tx, use of Azathioprine and >or=3 doses of ATG. CMV mismatch and CMV infection, rejection episodes and steroids were not risk factors. Despite reduction of immunosuppression, treatment consisted of surgical procedures to remove tumor masses (n = 6), Rituximab (n = 5), polychemotherapy (n = 3), antiviral (n = 1) and autologous T-cell therapy (n = 1). All patients demonstrated full remission without death related to PTLD or treatment at 3.9 (1.3-6.2) yr median follow-up time. The manifestation of PTLD in pediatric heart transplant recipients is associated with EBV infection and is predominantly in the form of a B-cell lymphoma. A tight and specific follow-up including early assessment of immunity status and specific therapeutic intervention to improve cellular immunity is warranted and may contribute to a significant reduction of PTLD-related morbidity and mortality.     

Post‐transplant lymphoproliferative disorders and other malignancies after pediatric intestinal transplantation: Incidence,clinical features and outcome

PTLDs are a well‐recognized and potentially fatal complication after intestinal transplantation. We analyzed the incidence, clinical features, and outcome in a 63 intestinal transplantation series performed in our unit between October 1999 and July 2011. Types of graft included ISB (n = 23), LSB (n = 20), and MV (n = 20). Patients were categorized into three groups of immunosuppression: I (n = 43) received basiliximab, tacrolimus, and steroids; II (n = 11) thymoglobulin and tacrolimus, and III (n = 9) alemtuzumab and tacrolimus. EBV status was serially assessed. All PTLD cases were biopsied to establish histopathological diagnosis. The incidence of PTLD was 14.2% (9/63). Median onset of PTLD after transplant was four months (range: 0.5–28), within first postoperative year in 6 (66.6%) patients. Fever was the most common symptom. Graft removal was needed in four patients (44%). The patient survival rate was 66.6% (6/9). We have not found any association between PTLD and immunosuppression regimen or transplant type. However, there was a statistical association with EBV active infection.     

Epstein-Barr virus associated disease following blood or marrow transplant

EBV associated disease continues to be a problem in the post-BHT population. The pathogenesis, risk factors, and diagnosis of PTLD, as well as the rationale, efficacy and advantages/disadvantages of various prophylactic, pre-emptive and treatment strategies are discussed.     

Use of calcium-channel blockers in pediatric renal transplant recipients

Hypertension (HTN) is a significant problem in pediatric renal transplant (TP) recipients, predisposing the individuals to the development of cardiovascular disease and graft dysfunction. Calcium channel blockers (CCB) are considered excellent agents to treat post-TP HTN. We compared the efficacy and adverse effects of the two most commonly prescribed CCBs in our pediatric renal TP population: nifedipine (Procardia, or P) and amlodipine (Norvasc, or N). All patients (n = 24) had been started on a CCB for systolic (SBP) and/or diastolic BP (DBP) > 95%. There were no other changes in adjunctive antihypertensive medications or doses during the cross-over period. Post-TP, pretreatment (pretx) SBP was 137.6 +/- 10.9 mmHg. The post-treatment SBP were (in mmHg): 128.5 +/- 11.9 (all patients, n = 24) (p = 0.009 vs. pretx); 126.4 +/- 10.0 (P alone, n = 15) (p = 0.007 vs. pretx); 132.8 +/- 14.4 (P + other antihypertensive(s), n = 9) (p = 0.331, NS vs. pretx). The post-TP, pretreatment DBP was 88.2 +/- 11.1 mmHg. The post-treatment DBP were (in mmHg): 78.5 +/- 6.9 (all patients, n = 24) (p = 0.03 vs. pretx); 77.2 +/- 7.4 (P alone, n = 15) (p = 0.008 vs. pretx); 80.7 +/- 6.1 (P + other antihypertensive(s), n = 9) (p = 0.063, NS vs. pretx). P and N were equally effective in reducing SBP (p = 0.843, NS) and DBP (p = 0.612, NS). Cyclosporin A (CyA) dose (p = 0.81) and trough levels (p = 0.19) were similar in P- and N-treated patients. Calculated GFR was virtually identical in P- and N-treated patients (p = 0.89). Patients (or parents of) reported a higher incidence of various side-effects while receiving P, including headache, flushing, dizziness and leg cramps. Furthermore, 22/24 (91.7%) reported some degree of gingival hyperplasia during treatment with P, and all these patients reported a stabilization or reduction of hypertrophy after the switch from P to N. We conclude that CCBs (N) are efficacious drugs for the purpose of BP control and renal protection in pediatric renal TP recipients.     

Use of an immune function assay to monitor immunosuppression for treatment of post-transplant lymphoproliferative disorder

The first-line treatment for PTLD is reduction in immunosuppression, allowing partial reconstitution of cell-mediated immunity. However, there is a risk of inducing acute allograft rejection during clinical resolution of PTLD. A recently available assay, Immuknow, measures the cell-mediated immune response and could be used to monitor reduction of immunosuppression. We report a case of PTLD occurring in a pediatric kidney transplant recipient where the reduction in immunosuppression was serially followed using this assay and quantitative EBV-PCR. A rapid reduction to minimal immunosuppression was followed by resolution of PTLD. Later, when the cell-mediated immune response increased, with negative viral load, immunosuppression was gradually increased utilizing the assay to adjust dosing. Presently, there are no signs of PTLD and renal function remains normal.     

Epstein–Barr virus-related post-transplant lymphoproliferative disease in solid organ transplant recipients, 1988–97: A Canadian multi-centre experience

The aim of this work was to obtain information on the magnitude of the problem, disease characteristics, and clinical practices relating to post-transplant lymphoproliferative disease (PTLD) in Canadian institutions. Adult and pediatric Canadian solid organ transplant groups were sent a questionnaire between July and October 1998. Analyzable data were obtained from 33 transplant groups. For the period 1988-97, 90 cases of PTLD were seen among 4283 solid organ transplant recipients. The incidence of PTLD varied from 0 to 14.6%, with the highest rates in children. Lymph nodes were the sites most frequently affected. Among the classifiable lesions, the majority were monoclonal. The lesions were of B-cell origin in 42.2% and of T-cell in 15.6%. The lesions were classified as monomorphic in 31.1%, polymorphic 18.9%, and hyperplastic in 1.1%. Tumors were reported as low grade in 26.7% and high grade in 10%. The majority of patients (71.1%) received reduced immunosuppression. Anti-viral agents were used in 52.2%. Chemotherapy was used in 27.8%, while immune globulin was used in 22.2%. Surgical resection was used in 20.0%, radiotherapy in 14.4%, and interferon-alpha therapy in 12.2%. The results showed that 48.9% of the patients had died, while 25.6% and 8.9% were regarded as having complete remission and partial remission, respectively. In conclusion, the incidence of PTLD varies widely across Canadian centres. Children are disproportionately affected and the mortality rate is high. Management practices vary significantly, and the need for information sharing was identified as one way of optimizing management.