Aggressive Epstein‐Barr virus‐negative B‐cell post‐transplant lymphoproliferative disorder in a hepatitis C‐negative liver transplant recipient who received a hepatitis C‐positive graft: Implications for D+/R− hepatitis C virus seroconversion

Post‐transplant lymphoproliferative disorder (PTLD) is an uncommon, but well‐described complication after liver transplantation. Most recently, Hepatitis C virus (HCV) has been implicated in the development of PTLD. A HCV‐negative 62‐year‐old man with autoimmune hepatitis received a HCV nucleic acid amplification test‐positive liver graft from a 73‐year‐old brain‐dead donor (D+/R?). After his recovery from the operation, the patient was treated for HCV and achieved an undetectable viral load. He was readmitted 6 months after transplant with a spontaneous perisplenic hematoma, weight loss, failure to thrive, low‐grade fevers, and abnormal liver function tests. He had a rapid clinical deterioration and expired shortly after admission. His liver biopsy demonstrated EBV‐negative monomorphic B‐cell PTLD. Our case is the first to report an aggressive early‐onset EBV‐negative monomorphic B‐cell PTLD in a HCV D+/R? liver transplant. This case illustrates the paucity of knowledge on HCV seroconversion and its involvement in EBV‐negative monomorphic B‐cell PTLD development.     

Long‐term remission in an adult heart transplant recipient with advanced Burkitt’s lymphoma post‐transplant lymphoproliferative disorder after anthracycline‐free chemotherapy: A case report and literature review

Incidence of Burkitt's lymphoma post‐transplant lymphoproliferative disorder (BL‐PTLD) in solid organ transplant (SOT) recipients in 1.4%‐1.6% with unknown cure rate. We report a case of Epstein‐Barr virus (EBV) positive, late‐onset BL‐PTLD in a 24‐year‐old EBV donor positive/recipient negative female. This is the first reported case of advanced BL‐PTLD post‐heart transplant in an adult. This is also the first reported case of treatment of advanced BL‐PTLD in a heart transplant recipient with a combined chemotherapy regimen without anthracyclines to avoid cardiotoxicity. The patient received 6 cycles of R‐COEP (rituximab with cyclophosphamide, vincristine, etoposide, prednisone) over 6 months and subsequently 3 cycles of high‐dose methotrexate (MTX) over 3 months for CNS prophylaxis. She remains without evidence of disease at 19 months post‐treatment. This case demonstrates that an anthracycline‐free regimen can be the therapy option for patients with BL‐PTLD after heart transplantation.     

Treatment of rare co‐occurrence of Epstein–Barr virus‐driven post‐transplant lymphoproliferative disorder and hemophagocytic lymphohistiocytosis after allogeneic stem cell transplantation

In both conditions, post‐transplant lymphoproliferative disorder (PTLD) and hemophagocytic lymphohistiocytosis (HLH), infection with Epstein–Barr virus (EBV) is a key mechanism: almost all PTLD in allogeneic stem cell transplantation (alloSCT) is caused by EBV‐related neoplastic lymphoproliferation, and secondary HLH is most frequently triggered by EBV infection. Therefore, concomitant EBV‐driven PTLD and HLH early after alloSCT require an approach to eliminate EBV and balance immune activation simultaneously. We report on a patient who developed simultaneous PTLD and signs of HLH on day 64 after alloSCT. Treatment was comprised of stopping cyclosporine, short‐course dexamethasone, and 3 courses of rituximab. The patient showed full recovery and complete remission of lymphadenopathy. This result indicates that immediate reduction in EBV‐carrying B cells by rituximab, suppression of general inflammation, and parallel support of reconstitution of long‐term T‐cell function, might be an appropriate therapeutic approach in this rare situation.     

Epstein‐Barr virus post‐transplant lymphoproliferative disease (PTLD) after hematopoietic stem cell transplantation

Epstein‐Barr virus (EBV) viremia and post‐transplant lymphoproliferative disease (PTLD) are severe complications after hematopoietic stem cell transplantation (HSCT). A series of risk factors have been found to predict EBV viremia and PTLD, including the T‐cell depletion, reduced intensity conditioning, and alternative donor. The rituximab pre‐emptive therapy could improve PTLD prognosis significantly, but the trigger of initiating rituximab pre‐emptive therapy has not been well established. Additionally, EBV‐specific cytotoxic T cell (CTL) is a promising approach to treat EBV‐PTLD.     

Epstein–Barr virus‐associated pneumonia in patients with post‐transplant lymphoproliferative disease after hematopoietic stem cell transplantation

Q.‐F. Liu, Z.‐P. Fan, X.‐D. Luo, J. Sun, Y. Zhang, Y.‐Q. Ding. Epstein–Barr virus‐associated pneumonia in patients with post‐transplant lymphoproliferative disease after hematopoietic stem cell transplantation.
Transpl Infect Dis 2010: 12: 284–291. All rights reserved. Abstract: Epstein–Barr virus (EBV) reactivation or infection after hematopoietic stem cell transplantation (HSCT) most often induces post‐transplant lymphoproliferative disease (PTLD), but it also may be associated with clinical symptoms such as pneumonia. Our aim was to investigate and describe the clinical manifestations of PTLD and PTLD accompanied by EBV‐associated pneumonia in 323 patients after HSCT. PTLD within extravisceral lymphoid tissue was identified in 7 cases (5 with CD20⁺ diffuse large B‐cell lymphoma, 1 with CD20⁺ polymorphic B‐cell hyperplasia, and 1 with CD3⁺CD45RO⁺ peripheral T‐cell lymphoma unspecified). Six of the patients with PTLD were EBV positive. Three patients had EBV‐associated pneumonia, and chest computed tomography revealed multifocal patchy and diffuse ground‐glass attenuation in both lungs. EBV‐DNA was positive in bronchoalveolar lavage (BAL) fluid, which contained mainly CD3⁺ T cells but no CD19⁺ or CD20⁺ B cells. Lung biopsy showed interstitial intra‐alveolar infiltrates of mainly CD3⁺ T cells and some CD68⁺ macrophages without CD19⁺ and CD20⁺ B cells. The patients with PTLD accompanied by EBV‐associated pneumonia developed hyperpyrexia and dyspnea, which progressed rapidly, and eventually all died within 2 weeks of the onset of PTLD. EBV‐associated PTLD accompanied by EBV‐associated pneumonia after HSCT is rare. Cytology of BAL fluid and lung biopsy may help establish the diagnosis.     

Acute cellular rejection and Epstein–Barr virus‐related post‐transplant lymphoproliferative disorder in a pediatric lung transplant with low viral load

F. Calabrese, M. Loy, F. Lunardi, D. Marino, S.M.L. Aversa, F. Rea. Acute cellular rejection and Epstein–Barr virus‐related post‐transplant lymphoproliferative disorder in a pediatric lung transplant with low viral load.
Transpl Infect Dis 2010: 12: 342–346. All rights reserved. Abstract: We report the case of an 18‐year‐old male who underwent bilateral lung transplantation for end‐stage cystic fibrosis. No Epstein–Barr virus (EBV) or cytomegalovirus serology mismatch was detected on pre‐transplant evaluation (donor and recipient were both positive). Two months after lung transplantation a computed tomography scan showed multiple nodules throughout both lungs. At that time a low EBV DNA blood level was detected (<300 copies/100,000 lymphomonocytes). Scheduled follow‐up transbronchial biopsy (TBB) revealed a prevalent finding characterized by perivascular lymphoid infiltrates with endothelitis. Extensive tissue coagulative necrosis with peripheral areas of dense aggregates of larger lymphoid cells were detected in the trans‐thoracic fine needle core biopsy (FNCB) performed on the largest nodule. The immunophenotypic profile characterized the perivascular lymphoid cells in TBB as mainly composed of T lymphocytes (CD3 positive) while the larger number of lymphocytes in FNCB as B cells (CD20 positive). In situ hybridization for EBV (EBER mRNA) was negative in TBB while it was positive in many lymphocytes of the FNCB. Real‐time polymerase chain reaction (PCR) for EBV was performed on paraffin‐embedded FNCB and detected a high quantity of EBV genomes (1260 copies/cell). IgH gene rearrangement using a fragment size PCR technique revealed a monoclonal B‐cell population in FNCB. Morphological and molecular findings suggest a final diagnosis of acute cellular rejection and a post‐transplant lymphoproliferative disorder (PTLD) EBV‐related in a lung transplant recipient with a low EBV DNA blood level. A possible coexistence of PTLD and acute rejection should be considered both for diagnosis and treatment. EBV PCR in the peripheral blood is a useful screening tool in transplant recipients; however, rare cases with PTLD may not have detectable levels of EBV DNA. This aspect should be taken into consideration to avoid false negatives.     

Post‐transplant lymphoproliferative disorder of the adrenal gland after allogeneic hematopoietic stem cell transplantation: report of two cases and literature review

Post‐transplant lymphoproliferative disorder (PTLD) is one of the life‐threatening complications after hematopoietic stem cell transplantation (HSCT) and solid organ transplantation (SOT), and it is associated almost exclusively with Epstein–Barr virus (EBV). We herein report 2 cases of EBV‐associated PTLD after allogeneic HSCT localized in the adrenal gland. Both patients developed adrenal tumor within 3 months after HSCT and were successfully treated with rituximab or tapering immunosuppressive agents. Both remained alive without recurrence. A literature review revealed 12 reported cases of PTLD involving the adrenal gland, but the adrenal gland was involved as one of the lesions of advanced‐stage PTLD after SOT. To the best of our knowledge, this is the first report to show cases of isolated EBV‐associated adrenal PTLD after HSCT. PTLD should be recognized as one of the causes of isolated adrenal tumor after HSCT.     

Low viral load post‐transplant lymphoproliferative disease localized within the tongue

Abstract: Post‐transplant lymphoproliferative disease (PTLD) can occur in different sites, such as lymph nodes, allograft, and central nervous system. We report a 6‐year‐old girl with end‐stage renal disease secondary to hypoplastic–dysplastic kidneys, who received a kidney transplant. Thirty months post transplant, she developed PTLD in the tongue, an area of muscular tissue only. At that time her peripheral blood Epstein–Barr viral (EBV) load was only 40 copies/10⁵ lymphocytes, though the tumor was EB early RNA (EBER) positive. Immunosuppression was reduced with initial improvement in her symptoms. One month later, she returned with abdominal complaints and a contained cecal abscess. The excised cecal tissue revealed CD20 and EBER‐positive lymphoid cells. At the same time, her peripheral blood EBV copy number rose to 400 copies/10⁵ lymphocytes. She was successfully treated for the progressive PTLD by complete cessation of immunosuppression and a modified reduced‐dose chemotherapy protocol plus rituximab. Partial immunosuppression was eventually re‐introduced with sirolimus and prednisone. She remains in remission 60 months post transplant, and 30 months post PTLD, with serum creatinine value maintained at 1.3 mg/dL. Unusual localization of PTLD to areas in non‐lymphoid tissue without regional lymphoid involvement may result in misleading low peripheral blood EBV viral loads.     

Isolated cerebral manifestation of Epstein–Barr virus‐associated post‐transplant lymphoproliferative disorder after allogeneic hematopoietic stem cell transplantation: a case of clinical and diagnostic challenges

N.A. Kittan, F. Beier, K. Kurz, H.H. Niller, L. Egger, W. Jilg, R. Andreesen, E. Holler, G.C. Hildebrandt. Isolated cerebral manifestation of Epstein–Barr virus‐associated post‐transplant lymphoproliferative disorder after allogeneic hematopoietic stem cell transplantation: a case of clinical and diagnostic challenges.
Transpl Infect Dis 2011: 13: 524–530. All rights reserved Abstract: We present the case of a 49‐year‐old male patient with Epstein–Barr virus (EBV)‐associated post‐transplant lymphoproliferative disorder (PTLD) limited to the brain that occurred 6 months after allogeneic hematopoietic stem cell transplantation (HSCT). Clinical symptoms included mental confusion, ataxia, and diplopia. Magnetic resonance imaging (MRI) revealed cerebellar and periventricular lesions consistent with an inflammatory process. Cerebrospinal fluid (CSF) analysis, but not peripheral blood, was positive for EBV‐DNA, but no malignant cells were found. Brain biopsy was not feasible because of low platelet counts. As we considered a diagnosis of either EBV‐associated encephalitis or PTLD, the patient was treated with rituximab combined with antiviral therapy. However, the cerebral lesions progressed and follow‐up CSF testing revealed immunoglobulin H clonality as evidence of a malignant process. Subsequent treatment attempts included 2 donor lymphocyte infusions (DLI). Despite treatment, the patient died from autopsy‐proven PTLD within 8 weeks of the onset of symptoms. This case demonstrates the clinical and diagnostic challenges of primary cerebral PTLD in a patient following allogeneic HSCT.     

Subacute immune response to primary EBV infection leading to post‐transplant lymphoproliferative disease in a renal transplant patient

A 23‐year‐old man sero‐negative for Epstein–Barr virus (EBV) developed recurrent sore throats 3 and 6 months after a renal transplant from an EBV sero‐positive donor. Tonsillar biopsy at 9 months post‐transplant showed post‐transplant lymphoproliferative disease (PTLD) caused by EBV. Following reduction of immunosuppressive treatment, he developed further signs and symptoms, and serological evidence of infectious mononucleosis followed by resolution of lymphadenopathy. This case emphasizes the difficulty in interpreting EBV serology in immunosuppressed patients and the importance of pre‐transplant EBV serology.     

Epstein‐Barr virus associated post‐transplant lymphoproliferative disorder mimicking acute graft versus host disease

We present a case series of 3 patients to highlight the fact that PTLD post‐transplant can mimic GVHD, and should be part of the differential diagnosis for diarrhea post allo‐HCT. Awareness of this presentation has important therapeutic implications, as increased immune suppression for the management of GVHD, can worsen clinical features of PTLD. Diagnostic imaging and tissue biopsies should be undertaken early in post‐transplant patients presenting with diarrhea or hepatic abnormalities, especially with atypical presentations like fever, and EBV PCR monitoring can expedite clinical decision‐making in such complicated scenarios while awaiting results of gut biopsies.     

A retrospective analysis of post‐transplant lymphoproliferative disorder following liver transplantation

Objective

To evaluate response rates and survival in adults developing post‐transplant lymphoproliferative disorder (PTLD) following liver transplantation.

Methods

Patients were identified retrospectively and data collected through local liver and haematology electronic databases and pharmacy records.

Results

Forty‐five patients were identified. The median age at first transplant and at development of PTLD was 48 and 54 years, respectively, with the median time from transplant to PTLD diagnosis of 56 months. The majority of cases (76%) were monomorphic B‐cell lymphomas, and 36% of tumours were EBV positive. Treatment involved reduction in immune‐suppression (RIS) in 30 (67%) with RIS the only treatment in 3. Ten (22%) patients were treated with rituximab alone, 13 (29%) with chemotherapy alone and 14 (31%) patients were treated with rituximab and chemotherapy. Twenty‐six (58%) patients achieved a complete response (CR). At a median follow‐up of 27 months, the median overall survival (OS) was 50 months. Response and OS were not associated with clinical factors or the use of rituximab.

Conclusion

Outcomes reported in this study are favourable and comparable to those reported previously. The addition of rituximab did not appear to have improved outcomes in this series, although a significant proportion of patients were able to avoid chemotherapy.     

Hashimoto's encephalopathy after interferon therapy for hepatitis C virus in adult liver transplant recipient accompanied by post‐transplant lymphoproliferative disorder related to Epstein–Barr virus infection

T. Hori, F. Oike, K. Hata, M. Nishikiori, Y. Ogura, K. Ogawa, Y. Takada, H. Egawa, J.H. Nguyen, S. Uemoto. Hashimoto's encephalopathy after interferon therapy for hepatitis C virus in adult liver transplant recipient accompanied by post‐transplant lymphoproliferative disorder related to Epstein–Barr virus infection
Transpl Infect Dis 2010: 12: 347–352. All rights reserved Abstract: A 55‐year‐old woman underwent living‐donor liver transplantation (LDLT). She had no history of autoimmune diseases. Spleen was preserved. Steroids were withdrawn at 3 months after LDLT. Epstein–Barr virus (EBV) infection occurred at 3.5 years after LDLT. Recurrent hepatitis C virus infection was confirmed at 4.5 years after LDLT, and pegylated interferon was introduced. Diagnosis of EBV‐positive post‐transplant lymphoproliferative disorder (PTLD) was made at 4.8 years after LDLT, and tacrolimus (Tac) was stopped completely. Then, unconsciousness, convulsion, and cervical stiffness appeared suddenly. Electroencephalography, cerebrospinal fluid analysis, and image studies revealed normal or only nonspecific findings. The patient was in a state of exhaustion; therefore, steroid pulse therapy (SPT) was attempted. Surprisingly, her general condition, including consciousness disturbance, was improved markedly, and Hashimoto's encephalopathy (HE) was suspected, based on this reaction to SPT. Elevations of anti‐thyroglobulin antibody and anti‐thyroid peroxidase antibody were confirmed. After withdrawal of Tac, and treatment with acyclovir and steroids, EBV‐positive PTLD and HE improved, although they recurred at 5.1 years after LDLT. SPT improved only neurological symptoms. Molecular‐targeted therapy was given for recurrent PTLD, based on analysis of sampling specimens. This therapy was effective, but tumor lysis syndrome occurred, and the patient died at 5.3 years after LDLT.     

First‐line use of rituximab correlates with increased overall survival in late post‐transplant lymphoproliferative disorders: retrospective,single‐centre study

This retrospective study evaluates the impact of rituximab on PTLD response and survival in a single‐centre cohort. PTLD cases between 1984 and 2009, including heart, kidney, liver and lung transplant recipients, were included. Survival was analysed taking into account the type of PTLD (monomorphic vs. polymorphic), EBV infection status, IPI score, Ann Arbor stage and use of rituximab. Among 1335 transplanted patients, 24 developed PTLD. Median age was 54 yr (range 29–69), median time to diagnosis 50 months (range 0–100). PTLD type was predominantly late/monomorphic (79% and 75%), mostly diffuse large B‐cell type. Overall response rate (ORR) was 62% (66% rituximab vs. 50% non‐rituximab; P = 0.5). R‐CHOP‐like regimens were used most frequently (72% of patients treated with rituximab). Median overall survival was 64 months (CI 95% 31–96). OS was significantly increased in patients treated with rituximab (P = 0.01; CI 95% rituximab 58–79 months; non‐rituximab 1–30 months). Post‐transplant immunosuppression regimen had no effect on survival or time to PTLD, except for cyclosporine A (CyA), which associated with increased time to PTLD (P = 0.02). Rituximab was associated with increased survival in our single‐centre series, and it should be considered as first‐line therapy for PTLD patients. The possible protective effect of CyA for development of PTLD should be prospectively evaluated.     

Managing the challenge of PTLD in liver and bowel transplant recipients

Post‐transplant lymphoproliferative disorder (PTLD) remains a common complication of liver and bowel transplantion. The ubiquity of Epstein‐Barr virus (EBV) combined with engraftment of organs rich with lymphatic tissue and the requirement of highly immunosuppressive regimens are factors that account for the high frequency and poor prognosis of PTLD in this population. Early detection of the virus followed by pre‐emptive reduction of immunosuppression are essential components in the management of PTLD, but can increase the risk of graft loss. More recently, the anti‐CD20 monoclonal antibody (rituximab) has been shown to improve survival in various transplant populations with PTLD, while other therapeutic options, such as chemotherapy, surgery or radiotherapy, have minimal clinical impact. EBV‐directed cytotoxic T cells have shown promise in the management of PTLD but clinical use is currently limited by lack of technical facilities worldwide.     

Umbilical cord blood transplantation in adults with advanced hodgkin's disease: high incidence of post‐transplant lymphoproliferative disease

We report the outcome of 30 consecutive patients with Hodgkin disease (HD) who underwent single‐unit UCBT. Most (90%) patients had failed previous autologous hematopoietic stem cell transplantation. The conditioning regimens were based on combinations of thiotepa, busulfan, cyclophosphamide or fludarabine, and antithymocyte globulin. The cumulative incidence (CI) of myeloid engraftment was 90% [95% confidence interval (C.I.), 74–98%] with a median of 18 d (range, 10–48). CI of acute graft‐versus‐host disease (GvHD) grades II–IV was 30% (95% C.I., 17–44%), while the incidence of chronic GVHD was 42% (95% C.I., 23–77%). The non‐relapse mortality (NRM) at 100 d and 4 yr was 30% (95% C.I., 13–46%) and 47% (95% C.I., 29–65%), respectively. EBV‐related post‐transplant lymphoproliferative disease (EBV‐PTLD) accounted for more than one‐third of transplant‐related death, with an estimate incidence of 26% (95% C.I., 9–44). The incidence of relapse at 4 yr was 25% (95% C.I., 9–42%). Four‐year event‐free survival (EFS) and overall survival (OS) were 28% and 30%, respectively. Despite a high NRM and an unexpected high incidence of EBV‐PTLD, UCBT in heavily pretreated HD patients is an option for patients lacking a suitable adult donor, provided the disease is not in refractory relapse.     

Epstein–Barr virus (EBV) genotypes among human immunodeficiency virus (HIV)‐related B‐cell Lymphomas and B‐cell post‐transplant lymphoproliferative disorders (B‐PTLD) – late‐onset lymphomas,especially in the HIV setting,are associated with type‐B‐EBV

We investigated 26 B‐cell post‐transplant lymphoproliferative disorders (B‐PTLD) and 15 human immunodeficiency virus‐related aggressive B‐cell lymphomas (HIV‐BCL) from England that were associated with Epstein–Barr virus (EBV) for the polymorphic sequences of the EBV‐encoded nuclear antigen 3C (EBNA3C) gene to distinguish the two different EBV strains. Type‐A‐EBV was identified in 92% of B‐PTLDS and in 53% of HIV‐BCL (P = 0.003). Among HIV‐BCL, patients associated with type‐B‐EBV had been HIV positive for significantly longer when compared to those associated with type‐A (P = 0.037) although there were no correlations with ethnicity, CD4 cell counts or plasma HIV viral load.     

Severe post‐transplant lymphoproliferative disorder after living donor liver transplantation

Post‐transplant lymphoproliferative disorder (PTLD) is a well‐known complication after transplantation. A living donor liver transplantation was performed on a 31‐year‐old man for fulminant hepatitis. He again developed liver dysfunction after 7 months. He was diagnosed as having acute cellular rejection and the steroid pulse therapy introduced resulted in little improvement. He gradually developed a high fever and right axillary lymphadenopathy appeared. Chest computed tomography (CT) was performed revealing small lung nodules and axillary lymphadenopathy. Because his serological status for Epstein–Barr virus was positive, PTLD was highly suspected and immunosuppression treatment was withdrawn with little improvement. One week later, he developed tachycardia. Chest CT was re‐performed revealing an infiltration to the left cardiac chamber. For diagnosis, axillary lymph node biopsy was performed and during the procedure, he developed ventricular tachycardia (VT). Immunohistological staining revealed PTLD of T lymphocytes, and chemotherapy was introduced on the same day he developed VT. After two cycles of tetrahydropyranyl, adriamycin, cyclophosphamide, vincristine, prednisolone and etoposide treatment, he completely recovered. This is a first case report of severe PTLD with VT, and our case implies the feasibility of chemotherapy after the appearance of dissemination symptoms.     

Epstein–Barr virus‐associated smooth muscle tumors in a composite tissue allograft and a pediatric liver transplant recipient

Epstein–Barr virus (EBV) is known to establish latent infections in B‐lymphocytes that can cause lymphoproliferative disorders particularly in immunocompromised patients. More recently, the development of rare EBV‐associated smooth muscle tumors has been reported in transplant recipients. We herein describe 2 new cases of EBV‐associated post‐transplant smooth muscle tumors (EBV‐PTSMT), including the first in a facial composite tissue graft recipient. Among the striking features shared by these 2 patients were their young ages, the fact that they were naïve for EBV before the transplantation, that they developed a post‐transplant lymphoproliferative disorder before the diagnosis of EBV‐PTSMT, and that they responded favorably to reduction of immunosuppression. Radiological and histologic features of EBV‐PTSMT are shown. Finally, pathophysiology and therapeutic management of EBV‐PTSMT are discussed based on a comprehensive review of the literature.     

Dynamic EBV gene loads in renal, hepatic, and cardiothoracic transplant recipients as determined by real-time PCR light cycler

BACKGROUND: Epstein-Barr virus (EBV) is recognised as one of the causative agents for most cases of post-transplant lymphoproliferative disease (PTLD). Elevated levels of EBV DNA are known to be associated with the onset of PTLD, but little information is available regarding how EBV loads change with time in asymptomatic transplant recipients following transplantation. Our aims were to study the trend of EBV loads in renal (RTx), hepatic, and cardiothoracic transplant recipients and to compare their EBV loads with other healthy and patient controls. METHODS: A prospective study was performed using a real-time TaqMan polymerase chain reaction technique to measure EBV DNA loads from three types of organ transplant recipients and haemodialysis patients (HD). Their results were then compared with those from the healthy controls (HC); monospot test negative (MN-) and infectious mononucleosis positive (IM+) patients; patients who were previously treated for PTLD (pPTLD); those who were currently diagnosed to have PTLD (PTLD+); and patients who had a stable renal, hepatic, or cardiothoracic graft for more than a year. RESULTS: Post-transplant EBV loads were significantly higher than the pre-transplant levels. Asymptomatic transplant recipients were differentiated from the PTLD+group at 600 genome copies of EBV/mug DNA, and from IM+group at 100 genome copies. Both HC and MN- groups had significantly lower EBV loads than the three transplant groups. The dynamic change of EBV loads in RTx was greater in the first post-transplant month when compared with the HD group. All transplant recipients had transient rises of EBV loads whereas EBV load continued to rise in one suspected PTLD patient. CONCLUSIONS: Asymptomatic transplant recipients had higher baseline post-transplant EBV levels than the non-transplant and MN- groups. The rising post-transplant EBV load in these transplant recipients did not seem to be sustained for longer than 2 weeks. However, in a PTLD+patient the rising EBV load continued over a period of 4 weeks. Hence, the dynamic pattern of EBV loads is more important than absolute EBV DNA measurements alone in identifying those who might go on to develop PTLD.