Kinetics of Epstein-Barr virus DNA load in different blood compartments of pediatric recipients of T-cell-depleted HLA-haploidentical stem cell transplantation

Mechanistic Understanding of EBV+Lymphoproliferative Disease Development After Transplantation

Posttransplant lymphoproliferative disorders (PTLDs) are among the most common malignant complications after transplantation, leading to a drastic reduction in patient survival rates. The majority of PTLDs are tightly linked to Epstein-Barr virus (EBV+PTLDs) and are the result of an uncontrolled proliferation of EBV-infected cells. However, although EBV infections are a common finding in transplant recipients, most patients with high EBV loads will never develop EBV+PTLD. Natural killer cells and EBV-specific CD8+ T lymphocytes are critical for controlling EBV-infected cells, and the impairment of these cytotoxic immune responses facilitates the unfettered proliferation of EBV-infected cells. Recent years have seen a considerable increase in available literature aiming to describe novel risk factors associated with the development of EBV+PTLD, which may critically relate to the strength of EBV-specific natural killer cell and EBV-CD8+ T lymphocyte responses. The accumulation of risk factors and the increased risk of developing EBV+PTLD go hand in hand. On the one hand, most of these risk factors, such as the level of immunosuppression or the EBV donor and recipient serologic mismatch, and distinct genetic risk factors are host related and affect cytotoxic EBV-specific immune responses. On the other hand, there is growing evidence that distinct EBV variants may have an increased malignant potential and are thus more likely to induce EBV+PTLD. Here, we aim to review, from a mechanistic point of view, the risk factors for EBV+PTLD in the host and the infecting EBV variants that may explain why only a minority of transplant recipients develop EBV+PTLD.

Human Cytomegalovirus and Epstein-Barr virus specific immunity in patients with ulcerative colitis

Human Cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) are endowed with the ability of establishing lifelong latency in human hosts and reactivating in immunocompromised subjects, including patients suffering from ulcerative colitis (UC). We, therefore, aimed to investigate virus-specific immunity in UC patients. A cohort of 24 UC patients (14 responders and 10 refractory to therapy) and 26 control subjects was prospectively enrolled to undergo virus-specific serology (by ELISA assay) and assessment of both CD4⁺ and CD8⁺ virus-specific T-cell response (by interferon-γ enzyme-linked immunospotanalysis). In parallel, mucosal viral load was determined by quantitative real-time PCR and the values were correlated with both clinical and endoscopic indexes of activity. For statistics, the t-test, Mann-Withney test, Fisher's exact test and Spearman rank correlation test were applied; p < 0.05 was considered significant. EBV-specific CD4⁺ and CD8⁺ T-cell responses were significantly lower in UC patients compared to controls (p < 0.0001 and p = 0.0006, respectively), whereas no difference was found for HCMV-specific T-cell response. When dividing the UC group according to response to therapy, both responders and refractory UC patients showed a deficient EBV-specific CD4⁺ T-cell response with respect to controls (p < 0.04 and p = 0.0003, respectively). Moreover, both EBV and HCMV mucosal loads were significantly higher in refractory UC than in responders and controls (p = 0.007 and 0.003; and p = 0.02 and 0.001, respectively), and correlated with activity indexes. Steroid therapy seemed the main risk factor for triggering EBV colitis. Finally, no cases of IgM positivity were found in the study population. An impaired EBV-specific immunity was clearly evident in UC patients, mostly in those refractory to therapy. The ELISPOT assay may serve as new tool for quantifying and monitoring virus-specific T-cell immunity in UC.

Post-transplantation lymphoproliferative disorder after haematopoietic stem cell transplantation

Post-transplantation lymphoproliferative disorder (PTLD) is a severe complication of haematopoietic stem cell transplantation (HSCT), occurring in a setting of immune suppression and dysregulation. The disease is in most cases driven by the reactivation of the Epstein-Barr virus (EBV), which induces B cell proliferation through different pathomechanisms. Beyond EBV, many factors, variably dependent on HSCT-related immunosuppression, contribute to the disease development. PTLDs share several features with primary lymphomas, though clinical manifestations may be different, frequently depending on extranodal involvement. According to the WHO classification, histologic examination is required for diagnosis, allowing also to distinguish among PTLD subtypes. However, in cases of severe and abrupt presentation, a diagnosis based on a combination of imaging studies and EBV-load determination is accepted. Therapies include prophylactic and pre-emptive interventions, aimed at eradicating EBV proliferation before symptoms onset, and targeted treatments. Among them, rituximab has emerged as first-line option, possibly combined with a reduction of immunosuppression, while EBV-specific cytotoxic T lymphocytes are effective and safe alternatives. Though prognosis remains poor, survival has markedly improved following the adoption of the aforementioned treatments. The validation of innovative, combined approaches is the future challenge.

18F-FDG PET/CT for Evaluation of Post-Transplant Lymphoproliferative Disorder (PTLD)

Post-transplant lymphoproliferative disorders (PTLD) are a spectrum of heterogeneous lymphoproliferative conditions that are serious and possibly fatal complications after solid organ or allogenic hematopoietic stem cell transplantation. Most PTLD are attributed to Epstein-Barr virus reactivation in B-cells in the setting of immunosuppression after transplantation. Early diagnosis, accurate staging, and timely treatment are of vital importance to reduce morbidity and mortality. Given the often nonspecific clinical presentation and disease heterogeneity of PTLD, tissue biopsy and histopathological analysis are essential to establish diagnosis and most importantly, determine the subtype of PTLD, which guides treatment options. Advanced imaging modalities such as ¹⁸F-FDG PET/CT have played an increasingly important role and have shown high sensitivity and specificity in detection, staging, and assessing treatment response in multiple clinical studies over the last two decades. However, larger multicenter prospective validation is still needed to further establish the clinical utility of PET imaging in the management of PTLD. Significantly, new hybrid imaging modalities such as PET/MR may help reduce radiation exposure, which is especially important in pediatric transplant patients.

Human Herpes Virus 7-related encephalopathy in children

BACKGROUND

Primary HHV7 infection is almost ubiquitous, and it can present as exanthema subitem. Little is known on the clinical relevance of HHV7 neuroinvasion in immunocompetent children.

METHODS

We describe 12 patients (median age 9.45 years, 50% males) with acute encephalopathy and active HHV7 infection. In all patients, HHV7-DNA was detected on cerebrospinal fluid (CSF) by RT-PCR.

RESULTS

7/12 patients had meningoencephalitis (two with ADEM and one with MOG antibody-associated CIS); 5/12 showed acute neuropsychiatric symptoms. EEG showed anomalies exclusively in patients with meningoencephalitis. Six patients had RMN anomalies. CSF HHV7 copies ranged between 20 and 3,500 copies/mL (median 66 copies/mL) and mean HHV7 CSF/blood ratio was 0.75. Outcome was favorable in all children, although 3/12 had minor neurobehavioral sequelae. Mean follow-up period of 5.2 months.

CONCLUSIONS

HHV7 can determine neuroinvasion in immunocompetent children, leading to acute encephalopathy. Blood-brain barrier damage and high CSF/blood viral copies ratio correlated with a more severe presentation. We speculate on the importance of immune-mediated mechanisms in provoking clinical features.

EBV DNA increase in COVID-19 patients with impaired lymphocyte subpopulation count

Objectives

The immunologic profile and opportunistic viral DNA increase were monitored in Italian patients with COVID-19 in order to identify markers of disease severity.

Methods

A total of 104 patients infected with SARS-CoV-2 were evaluated in the study. Of them, 42/104 (40.4%) were hospitalized in an intensive care unit (ICU) and 62/104(59.6%) in a sub-intensive care unit (SICU). Human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV), Parvovirus B19 and Human Herpesvirus 6 virus reactivations were determined by real-time PCR, and lymphocyte subpopulation counts were determined by flow cytometry.

Results

Among opportunistic viruses, only EBV was consistently detected. EBV DNA was observed in 40/42 (95.2%) of the ICU patients and in 51/61 (83.6%) of the SICU patients. Comparing the two groups of patients, the EBV DNA median level among ICU patients was significantly higher than that observed in SICU patients. In parallel, a significant reduction of CD8 T cell and NK count in ICU patients as compared with SICU patients was observed (p < 0.05). In contrast, B cell count was significantly increased in ICU patients (p = 0.0172).

Conclusions

A correlation between reduced CD8⁺ T cells and NK counts, EBV DNA levels and COVID-19 severity was observed. Other opportunistic viral infections were not observed. The relationship between EBV load and COVID-19 severity should be further evaluated in longitudinal studies.

Management of PTLD After Hematopoietic Stem Cell Transplantation: Immunological Perspectives

Post-transplant lymphoproliferative disorders (PTLDs) are life-threatening complications of iatrogenic immune impairment after allogeneic hematopoietic stem cell transplantation (HSCT). In the pediatric setting, the majority of PTLDs are related to the Epstein-Barr virus (EBV) infection, and present as B-cell lymphoproliferations. Although considered rare events, PTLDs have been increasingly observed with the widening application of HSCT from alternative sources, including cord blood and HLA-haploidentical stem cell grafts, and the use of novel agents for the prevention and treatment of rejection and graft-vs.-host disease. The higher frequency initially paralleled a poor outcome, due to limited therapeutic options, and scarcity of controlled trials in a rare disease context. In the last 2 decades, insight into the relationship between EBV and the immune system, and advances in early diagnosis, monitoring and treatment have changed the approach to the management of PTLDs after HSCT, and significantly ameliorated the prognosis. In this review, we summarize literature on the impact of combined viro-immunologic assessment on PTLD management, describe the various strategies for PTLD prevention and preemptive/curative treatment, and discuss the potential of novel immune-based therapies in the containment of this malignant complication.

Donor CMV-specific cytotoxic T lymphocytes successfully treated drug-resistant cytomegalovirus encephalitis after allogeneic hematopoietic stem cell transplantation

Background: Cytomegalovirus (CMV) infection of the central nervous system (CNS) is a rare but life-threatening complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT).Cases presentation: Two patients with drug-resistant CMV encephalitis after allo-HSCT were successfully treated with donor CMV-specific cytotoxic T lymphocytes (CTLs). In the first case, a 27-year-old male who received haploidentical transplantation to treat T-cell acute lymphoblastic leukemia (T-ALL), developed CMV encephalitis during the time of the ganciclovir maintenance treatment. After intravenous foscarnet and donor CMV-specific CTLs, CMV-DNA of CSF became undetectable and the abnormal signs of brain magnetic resonance imaging (MRI) were limited. Another case, a 57-year-old female with acute myeloid leukemia (AML) who underwent haploidentical transplantation, also developed CMV encephalitis during the maintenance treatment of the ganciclovir. After administering donor CMV-specific CTLs intrathecally, the CMV load of the CSF decreased.Conclusions: The intravenous/intratheca administration of donor CMV-specific CTLs may be a safe and effective treatment for CMV encephalitis, especially for patients who suffered from drug-resistant CMV infection.

Impaired virus-specific T cell responses in patients with myeloproliferative neoplasms treated with ruxolitinib

Ruxolitinib is effective in myeloproliferative neoplasms (MPN) but can cause reactivation of silent infections. We aimed at evaluating viral load and T-cell responses to human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) in a cohort of 25 MPN patients treated with ruxolitinib. EBV-DNA and HCMV-DNA were quantified monthly using real-time polimerase chain reaction (PCR) on peripheral blood samples, and T-cell subsets were analyzed by flowcytometry. HCMV and EBV-directed T-cell responses were evaluated using the IFN-γ ELISPOT assay. Most patients had CD4+ and/or CD8+ T-cells below the normal range; these reductions were related to the duration of ruxolitinib treatment. In fact, reduced T-lymphocytes' subsets were found in 93% of patients treated for ≥5 years and in 45% of those treated for <5 years (P = .021). The former also had lower median numbers of CD4+ and CD8+ cells. Subclinical reactivation of EBV and HCMV occurred in 76% and 8% of patients. We observed a trend to an inverse relationship between EBV and CMV-specific CD4+ and CD8+ T-cell responses and viral load, and a trend to an inverse correlation with ruxolitinib dose. Therefore, our data suggest that the ruxolitinib treatment may interfere with immunosurveillance against EBV and HCMV.

Evaluation of EBV- and HCMV-Specific T Cell Responses in Systemic Lupus Erythematosus (SLE) Patients Using a Normalized Enzyme-Linked Immunospot (ELISPOT) Assay

Systemic lupus erythematosus (SLE) is an autoimmune disease with a complex etiology. Opportunistic viral pathogens, such as human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV), are particularly relevant. The role of the T cell response in SLE has not been deeply studied; we investigated the role of HCMV- and EBV-specific T cell responses in SLE patients also in relation to their pharmacological immunosuppressive status. PBMCs from 70 SLE patients and 50 healthy controls were stimulated with EBV- and HCMV-specific antigens, and IFN-γ-secreting T cells were quantified. We observed that both EBV- and HCMV-specific T cell responses were significantly lower in SLE patients compared with healthy subjects. We reported decreased EBV- and HCMV-specific T cell responses among medium-high immunosuppressed patients compared to low immunosuppressed patients. Immunosuppressive level could exert a role in the control of herpesviruses reactivation, even if the immunosuppressive condition of SLE remains the driving cause of skewed virus-specific T cell response.

Lytic EBV infection investigated by detection of Soluble Epstein-Barr virus ZEBRA in the serum of patients with PTLD

The ZEBRA protein (encoded by the BZLF1 gene), is the major transcription factor of EBV, expressed upon EBV lytic cycle activation. Several studies highlighted the critical role of EBV lytic infection as a risk factor for lymphoproliferative disorders like post-transplant lymphoproliferative disease (PTLD). Here, we use an antigen-capture ELISA assay specifically designed to detecting the circulating soluble ZEBRA (sZEBRA) in serum samples (threshold value determined at 40ng/mL). We retrospectively investigated a population of 66 transplanted patients comprising 35 PTLD. All the samples from a control population (30 EBV-seronegative subjects and 25 immunocompetent individuals with EBV serological reactivation), classified as sZEBRA < 40ng/mL were assigned as negative. At PTLD diagnosis, EBV genome (quantified by qPCR with EBV DNA>200 copies/mL) and sZEBRA were detectable in 51% and 60% of cases, respectively. In the patients who developed a pathologically-confirmed PTLD, the mean sZEBRA value in cases, was 399 ng/mL +/− 141 versus 53ng/mL +/− 7 in patients who did not (p  < 0,001). This is the first report relating to the detection of the circulating ZEBRA in serum specimens, as well as the first analysis dealing with the lytic cycle of EBV in PTLD patients with this new biomarker.

Pre-emptive rituximab for Epstein-Barr virus reactivation after haplo-hematopoietic stem cell transplantation

BACKGROUND

Epstein-Barr virus-related post-transplantation lymphoproliferative disease (EBV-PTLD) is a serious complication in hematopoietic stem cell transplantation (HSCT) recipients.

METHODS

We conducted a retrospective study to investigate the incidence and potential risk factors for EBV reactivation and to assess the efficacy of the management of EBV reactivation with pre-emptive rituximab in children who had T-cell-replete haploidentical HSCT (TCR-haplo-SCT) with low-dose anti-thymocyte globulin (ATG). EBV-DNA level in peripheral blood (PB) was measured when suspected EBV reactivation were observed. When the EBV-DNA level in PB increased to >1,000 copies/10⁶ peripheral blood mononuclear cells (PBMC), patients were pre-emptively treated with rituximab (375 mg/m² /dose).

RESULTS

A total of 19 (50%) of 38 patients received rituximab infusion at a median time of 56 days after HSCT (range, 17-270 days). The median viral load at initiation of therapy was 2,900 copies/10⁶ PBMC (range, 1,000-650 000). Pre-emptive therapy was started after a median of 2 days (range, 0-7 days). The median number of weekly treatment cycles was 2 (range, 1-3). None of the patients developed PTLD or other EBV-associated diseases.

CONCLUSION

Pre-emptive rituximab therapy could be a useful strategy for EBV-PTLD in TCR-haplo-SCT recipients with low-dose ATG.

Management of Epstein-Barr Virus infections and post-transplant lymphoproliferative disorders in patients after allogeneic hematopoietic stem cell transplantation: Sixth European Conference on Infections in Leukemia (ECIL-6) guidelines

Epstein-Barr virus-related post-transplant lymphoproliferative disorders are recognized as a significant cause of morbidity and mortality in patients undergoing hematopoietic stem cell transplantation. To better define current understanding of post-transplant lymphoproliferative disorders in stem cell transplant patients, and to improve its diagnosis and management, a working group of the Sixth European Conference on Infections in Leukemia 2015 reviewed the literature, graded the available quality of evidence, and developed evidence-based recommendations for diagnosis, prevention, prophylaxis and therapy of post-transplant lymphoproliferative disorders exclusively in the stem cell transplant setting. The key elements in diagnosis include non-invasive and invasive methods. The former are based on quantitative viral load measurement and imaging with positron emission tomography; the latter with tissue biopsy for histopathology and detection of Epstein-Barr virus. The diagnosis of post-transplant lymphoproliferative disorder can be established on a proven or probable level. Therapeutic strategies include prophylaxis, preemptive therapy and targeted therapy. Rituximab, reduction of immunosuppression and Epstein-Barr virus-specific cytotoxic T-cell therapy are recommended as first-line therapy, whilst unselected donor lymphocyte infusions or chemotherapy are options as second-line therapy; other methods including antiviral drugs are discouraged.

Differential cellular localization of Epstein-Barr virus and human cytomegalovirus in the colonic mucosa of patients with active or quiescent inflammatory bowel disease

The role of human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) in the exacerbation of inflammatory bowel disease (IBD) is still uncertain. We prospectively investigated the presence of EBV and HCMV infection in both epithelial and immune cells of colonic mucosa of IBD patients, both refractory and responders to standard therapies, in comparison with patients suffering from irritable bowel syndrome who were considered as controls, by using quantitative real-time polymerase chain reaction, immunohistochemistry and in situ hybridization, in an attempt to assess viral localization, DNA load, life cycle phase and possible correlation with disease activity indexes. We obtained clear evidence of the presence of high DNA loads of both viruses in either enterocytes or immune cells of refractory IBD patients, whereas we observed low levels in the responder group and an absence of detectable copies in all cell populations of controls. Remarkably, the values of EBV and HCMV DNA in inflamed mucosa were invariably higher than in non-inflamed areas in both IBD groups, and the EBV DNA loads in the cell populations of diseased mucosa of refractory IBD patients positively correlated with the severity of mucosal damage and clinical indexes of activity. Moreover, EBV infection resulted the most prevalent either alone or in combination with HCMV, while immunohistochemistry and in situ hybridization did not allow us to distinguish between the different phases of viral life cycle. Finally, as regards treatment, these novel findings could pave the way for the use of new antiviral molecules in the treatment of this condition.

Detection of Active Epstein-Barr Virus Infection in Duodenal Mucosa of Patients With Refractory Celiac Disease

Refractory celiac disease is characterized by mucosal damage in patients with celiac disease despite a gluten-free diet. Little is known about the mechanisms that cause persistent intestinal inflammation in these patients. We performed a case-control study of 17 consecutive patients diagnosed with refractory celiac disease from 2001 through 2014 (median age, 51 y; 10 women) and 24 patients with uncomplicated celiac disease (controls) to determine whether refractory disease is associated with infection by lymphotropic oncogenic viruses. We performed real-time PCR analyses of duodenal biopsy samples from all patients to detect Epstein-Barr virus (EBV), human herpesvirus-8, and human T-cell lymphotropic virus-I, -II, or -III. We used in situ hybridization and immunohistochemical analyses to identify infected cells and viral proteins. We did not detect human herpesvirus-8 or human T-cell lymphotropic viruses in any of the biopsy specimens. However, 12 of 17 (70.5%) biopsy specimens from patients with refractory celiac disease were positive for EBV, compared with 4 of 24 (16.6%) biopsy specimens from controls (P < .001). EBV was detected in inflammatory cells and enterocytes. An analysis of latency- and replication-associated proteins confirmed active infection. Further studies are needed to determine whether EBV infection contributes to the pathogenesis of refractory celiac disease and enteropathy-associated T-cell lymphoma.

T-lymphocyte subsets in lung transplant recipients: association between nadir CD4 T-cell count and viral infections after transplantation

BACKGROUND

Little is known about the kinetics of T-cell subsets in lung transplant recipients (LTR) and their association with the occurrence of opportunistic infections (OI).

OBJECTIVES

To analyze the kinetics of T-lymphocyte subsets in LTR and the association between nadir CD4 T-cell count and viral infections after transplantation.

STUDY DESIGN

Serial measurements of peripheral blood CD4 and CD8 T-cell counts obtained during the first year post-transplantation from 83 consecutive LTR and their correlation with both viral OI and community-acquired infections post-transplantation were retrospectively analyzed.

RESULTS

LTR with a nadir CD4 T-cell count <200 cells/μl had consistently lower CD4 and CD8 T-cell counts than LTR with a nadir CD4 T-cell count >200 cells/μl (p<0.001). In LTR with a nadir CD4 T-cell count <200 cells/μl, the cumulative incidence of viral infections detected in peripheral blood and in bronchoalveolar lavage (BAL) samples was higher than in LTR with a nadir CD4 T-cell count >200 cells/μl (p=0.0012 and p=0.0058, respectively). A nadir CD4 T-cell count <200 cells/μl within the first three months post-transplantation predicted a higher frequency of viral infectious episodes in BAL samples within the subsequent six month period (p=0.0066).

CONCLUSIONS

Stratification of patients according to nadir CD4 T-cell count may represent a new and simple approach for early identification of patients at risk for subsequent virus infections.

Epstein-Barr virus DNAemia in Iranian liver transplant recipients and assessment of its variation in posttransplant lymphproliferative disorder patients by quantitative polymerase chain reaction assay

OBJECTIVES

Epstein-Barr virus primary infection and/or reactivation may play a major role in the incidence of posttransplant lymphoproliferative disorder in organ recipients. We assessed Epstein-Barr virus viral load in liver transplant patients suspected of having Epstein-Barr virus/ posttransplant lymphoproliferative disorder at specified times after transplant and evaluated the clinical findings and posttransplant complications.

MATERIALS AND METHODS

In the 696 patients who underwent liver transplant in this retrospective study, Epstein-Barr virus viral load was examined intermittently in 127 liver transplant recipients who were suspected to have Epstein-Barr virus infection/disease. Sampling was performed during 4 years from July 2009 to May 2013 using real-time polymerase chain reaction assay. Clinical and pathologic data were gathered by reviewing medical records.

RESULTS

There were 78 of the 127 suspected patients (61%) who exhibited Epstein-Barr virus DNAemia and 19 patients had posttransplant lymphoproliferative disorder. The median EBV viral load of posttransplant lymphoproliferative disorder patients was significantly higher than unaffected patients. Posttransplant lymphoproliferative disorder was diagnosed clinically in 34 subjects (4.9%). Estimated mortality rate of posttransplant lymphoproliferative disorder patients was 35% during 1.5-year follow-up after transplant.

CONCLUSIONS

Monitoring Epstein-Barr virus load may enable detection of Epstein-Barr virus infection/disease in liver transplant patients suspected of having the virus, even several weeks before the onset of any clinical manifestations, especially in pediatric patients who have high incidence and mortality from posttransplant lymphoproliferative disorder.

Epstein-Barr virus serology and PCR: conflicting results in an immunocompetent host. A case report and review of literature

We present the case of a 27-year-old immunocompetent man who progressively developed a generalized lymphadenopathy and B symptoms. Results of Epstein-Barr virus (EBV) serology were suggestive for a past infection, but the EBV viral load in whole blood was high. Also, core needle biopsy of the largest lymph node showed an image which could fit an EBV-driven reactive lymphoproliferation. Despite the absence of an immune disorder, all medical evidence points to an EBV-driven lymphoproliferative proces. In immunocompetent patients, it seems extremely uncommon to detect a high EBV viral load in the absence of serological evidence of an acute EBV infection or reactivation. We reviewed literature on this topic and on the selection of the appropriate sample type for EBV PCR, as this is known to be a critical point. Serological testing for the diagnosis of EBV infection is the gold standard in immunocompetent patients. Measuring EBV viral load is only recommended when dealing with immunocompromised patients. Although extremely rare, this case report shows that there is a place for EBV PCR in certain situations in immunocompetent patients. Besides, there is still no consensus regarding the specimen of choice for the determination of the EBV viral load. The preferred specimen type seems to depend on the patient's underlying condition.

Systematic analysis of human oncogenic viruses in colon cancer revealed EBV latency in lymphoid infiltrates

Background

Environmental factors may play a role in colon cancer. In this view, several studies investigated tumor samples for the presence of various viral DNA with conflicting results.

Findings

We undertook a systematic DNA analysis of 44 consecutive, prospectively collected primary tumor samples by real time and qualitative PCR for viruses of known or potential oncogenic role in humans, including polyomavirus (JCV, BKV, Merkel cell polyomavirus), HPV, HTLV, HHV-8 and EBV. Negative controls consisted of surgical resection margins. No evidence of genomic DNA fragments from tested virus were detected, except for EBV, which was found in a significant portion of tumors (23/44, 52%). Real-time PCR showed that EBV DNA was present at a highly variable content (median 258 copies in 10⁵ cells, range 15–4837). Presence of EBV DNA had a trend to be associated with high lymphocyte infiltration (p = 0.06, χ2 test), and in situ hybridization with EBER1-2 probes revealed latency in a fraction of these lymphoid cells, with just a few scattered plasma cells positive for BZLF-1, an immediate early protein expressed during lytic replication. LMP-1 expression was undetectable by immunohistochemistry.

Conclusions

These results argue against a significant involvement of the tested oncogenic viruses in established colon cancer.

Duplex realtime PCR method for Epstein-Barr virus and human DNA quantification: its application for post-transplant lymphoproliferative disorders detection

INTRODUCTION

The quantification of circulating Epstein-Barr virus (EBV) DNA is used to monitor transplant patients as an early marker of Post-Transplant Lymphoproliferative Disorders (PTLD). So far no standardized methodology exists for such determination.

OBJECTIVE

Our purpose was to develop and validate a real-time PCR assay to quantify EBV DNA in clinical samples from transplant recipients.

METHODS

A duplex real-time PCR method was developed to amplify DNA from EBV and from a human gene. The EBV load was determined in peripheral blood mononuclear cells (PBMC), plasma and oropharyngeal tissue from 64 non-transplanted patients with lymphoid-hypertrophy (Non-Tx), 47 transplant recipients without PTLD (Tx), 54 recipients with PTLD (Tx-PTLD), and 66 blood donors (BD). WinPEPI, version 11.14 software was used for statistical analysis.

RESULTS

Analytical validation: the intra and inter-assays variation coefficients were less than 4.5% (EBV-reaction) and 3% (glyceraldehyde 3-phosphate dehydrogenase - GAPDH reaction). Linear ranges comprised 10(7)-10 EBV genome equivalents (gEq) (EBV-reaction) and 500,000-32 human gEq (GAPDH-reaction). The detection limit was 2.9 EBV gEq (EBV-reaction). Both reactions showed specificity. Application to clinical samples: higher levels of EBV were found in oropharyngeal tissue from transplanted groups with and without PTLD, compared to Non-Tx (p<0.05). The EBV load in PBMC from the groups of BD, Non-Tx, Tx and Tx-PTLD exhibited increasing levels (p<0.05). In BD, PBMC and plasma, EBV loads were undetectable.

CONCLUSIONS

The performance of the assay was suitable for the required clinical application. The assay may be useful to monitor EBV infection in transplant patients, in particular in laboratories from low-income regions that cannot afford to use commercial assays.

Successful treatment of a classic Hodgkin lymphoma-type post-transplant lymphoproliferative disorder with tailored chemotherapy and Epstein-Barr virus-specific cytotoxic T lymphocytes in a pediatric heart transplant recipient

CHL type is the least common major form of EBV-related PTLD but rarely occurs in pediatric recipients; development of CHL subsequent to other PTLD subtypes in the same transplant recipient is even more unusual. Because of its rarity, indications on the best treatment strategy are limited. Patients have been mostly treated with standard HL chemotherapy/radiotherapy, and prognosis seems more favorable than other monomorphic PTLDs. Herein, we describe a pediatric case of EBV-associated, stage IV-B, CHL arising in a heart allograft recipient eight yr after diagnosis of B-cell polymorphic PTLD. The patient was successfully treated with adjusted-dose HL chemotherapy and autologous EBV-specific CTL, without discontinuation of maintenance immunosuppression. At two yr from therapy completion, the patient is in CR with stable organ function. With this strategy, it may be possible to reproduce the good prognostic data reported for CHL-type PTLD, with decreased risk of organ toxicity or rejection.

Detection of Epstein-Barr virus-specific memory CD4+ T cells using a peptide-based cultured enzyme-linked immunospot assay

Approaches to evaluate T-cell responses to Epstein-Barr virus (EBV) include enzyme-linked immunospot (ELISPOT), which quantifies cells capable of immediate interferon-γ secretion upon antigen stimulation. However, evaluation of expandable EBV-specific memory T cells in an ELISPOT format has not been described previously. We quantified EBV-specific T-cell precursors with high proliferative capacity by using a peptide-based cultured interferon-γ ELISPOT assay. Standard and cultured ELISPOT responses to overlapping peptide pools (15-mers overlapping by 11 amino acids) covering the lytic (BZLF1 and BMRF1) and latent (EBNA1, EBNA3a, EBNA3b, EBNA3c, LMP1 and LMP2) EBV proteins were evaluated in 20 healthy subjects with remote EBV infection and, for comparison, in four solid organ transplant recipients. Cultured ELISPOT responses to both lytic and latent EBV antigens were significantly higher than standard ELISPOT responses. The distribution of EBV-specific T-cell responses detected in healthy virus carriers showed more consistent cultured ELISPOT responses compared with standard ELISPOT responses. T-cell responses quantified by cultured ELISPOT were mainly mediated by CD4+ T cells and a marked pattern of immunodominance to latent-phase antigens (EBNA1 > EBNA3 family antigens > LMP2 > LMP1) was shown. Both the magnitude and distribution of EBV-specific T-cell responses were altered in solid organ transplant recipients; in particular, cultured ELISPOT responses were almost undetectable in a lung-transplanted patient with EBV-associated diseases. Analysis of T-cell responses to EBV by ELISPOT assays might provide new insights into the pathogenesis of EBV-related diseases and serve as new tools in the monitoring of EBV infection in immunocompromised patients.

Determining EBV load: current best practice and future requirements

EBV, a gammaherpesvirus and the pathogenic agent for infectious mononucleosis, is also associated with a broad spectrum of lymphoid and epithelial malignancies in immunocompetent and immunosuppressed individuals. EBV-DNA-load measurement by PCR has been shown to be a potential tool for the diagnosis of these diseases, a prognostic factor of their outcome and a successful method to monitor immunosuppressed patients. Since the end of 2011, there is an international WHO standard reference for EBV quantification available; however, many questions still remain; for instance about the optimal amplified region of the EBV genome, or the best-used specimen for EBV detection. Additionally, the optimal specimen and amplified region may vary in different malignancies. In this article, the authors review the different methods to measure EBV load, focus on the best-used specimen for the different EBV-associated malignancies and discuss future requirements and opportunities for EBV-load measurement.

Epstein-Barr virus reactivation in allogeneic stem cell transplantation is highly related to cytomegalovirus reactivation

Monitoring of Epstein-Barr virus (EBV) load and pre-emptive rituximab is an appropriate approach to prevent post-transplant lymphoproliferative disease (PTLD) occurring after hematopoietic stem cell transplantation (HSCT). This pre-emptive approach, based on EBV-DNA monitoring through a quantitative polymerase chain reaction, was applied to 101 consecutive patients who underwent allo HSCT at our Institute (median age 50). A single infusion of rituximab was administered to 11 of 16 patients who were at high risk for progression to PTLD, defined as a DNA value >10 000 copies/mL. All patients cleared EBV DNAemia, without any recurrences. Main factors significantly associated with high risk for PTLD were as follows: (i) unrelated vs. sibling (26% vs. 7%; p = 0.011); (ii) T-cell depletion (29% vs. 6%; p = 0.001); (iii) graft versus host disease (GVHD; 30% vs. 7%; p = 0.002); and (iv) cytomegalovirus (CMV) reactivation (29% vs. 4%; p = 0.001). Multivariate analysis showed that CMV reactivation was the only independent variable associated with EBV reactivation. We conclude that: (i) a single infusion of rituximab is able to prevent the risk of progression into EBV-related PTLD; and (ii) CMV reactivation is strongly associated with EBV reactivation; therefore, an intensive EBV monitoring strategy could be advisable only in case of CMV reactivation.

Persistent low level Epstein-Barr virus DNAemia in childhood cancer survivors

BACKGROUND

Clinical observation of Epstein-Barr virus (EBV) status has not documented in childhood cancer survivors (CCSs) sustaining long-term remission of malignant diseases. Thus, the aim of this study was to evaluate the EBV status in children with various malignant diseases after they completed their treatments.

PATIENTS AND METHODS

Thirty consecutive children with various malignant diseases previously received treatment at the University of Tsukuba Hospital. Nine cases had acute lymphoblastic leukemia (ALL), 10 had solid tumors, 4 had lymphoma, 4 had CNS tumors, and 3 had acute myeloid leukemia (AML). EBV DNA in 328 whole blood samples were monitored by real-time QPCR for all cases after treatment. Clinical records and laboratory data were also reviewed.

RESULTS

There were 6/30 (20%) cases with continuous detection of EBV DNA while there were 24/30 (80%) cases without continuous EBV DNA. EBV DNAemia was persistently observed in 4/9 (44.4%) cases with ALL and in 2/4 (50%) cases with lymphoma. Persistent EBV DNAemia can be observed for >5 years without any EBV associated symptoms or diseases.

CONCLUSIONS

Childhood cancer survivors have persistent EBV DNAemia more frequently, which is thought to be observed in cases with ALL and lymphoma with higher tendency for >5 years after treatment. Persistent EBV DNAemia is frequent in CCSs aged 5-10 years. Any immunological alteration is speculative in a pathophysiology of persistent EBV DNAemia.

Prognostic factors and outcome of Epstein-Barr virus DNAemia in high-risk recipients of allogeneic stem cell transplantation treated with preemptive rituximab

AIMS AND METHODS

This study assessed incidence, predictive factors, and outcome of Epstein-Barr virus (EBV) DNAemia in 100 recipients of allogeneic hematopoietic stem cell transplant. A total of 68 patients received anti-thymocyte globulin before unrelated grafts.

RESULTS

Cumulative incidence of high-load EBV DNAemia defined by levels >10,000 copies/mL was 14% at 12 months. In multivariate analysis, a CD4+ T-lymphocyte count >50 μL at day +30 was the only factor significantly associated with a reduced risk of high-load EBV DNAemia. Thirteen of 16 patients with high viral loads were preemptively treated with rituximab and achieved EBV DNA negativity. Three patients had already developed post-transplant lymphoproliferative disorder (PTLD) at the time of detection of high EBV DNA loads, and they obtained complete response after rituximab infusions and chemotherapy. Patients with high EBV DNA load had a significantly higher transplant-related mortality (TRM) compared with patients with negative or low viral load (54% vs. 16%, P = 0.009) and a trend to lower overall survival (55% vs. 29%, P = 0.060).

CONCLUSION

We conclude that CD4+ cell count at day +30 is a predictive factor for EBV DNAemia and may help identify patients requiring closer monitoring. Although only 3% of patients progressed to PTLD and were all successfully managed, EBV reactivation was associated with higher TRM, mainly because of infections.

Epstein-Barr virus: general factors, virus-related diseases and measurement of viral load after transplant

The Epstein-Barr virus is responsible for infectious mononucleosis syndrome and is also closely associated to several types of cancer. The main complication involving Epstein-Barr virus infection, both in recipients of hematopoietic stem cells and solid organs, is post-transplant lymphoproliferative disease. The importance of this disease has increased interest in the development of laboratory tools to improve post-transplant monitoring and to detect the disease before clinical evolution. Viral load analysis for Epstein-Barr virus through real-time polymerase chain reaction is, at present, the best tool to measure viral load. However, there is not a consensus on which sample type is the best for the test and what is its predictive value for therapeutic interventions.

Differential outcome of neurological HCMV infection in two hematopoietic stem cell transplant recipients

BACKGROUND

Human cytomegalovirus (HCMV) infection of the central nervous system (CNS) is a rare but life threatening condition which may follow hematopoietic stem cell transplantation. Diagnosis, monitoring and treatment approaches rely on anecdotal reports.

CASE PRESENTATIONS

The different outcomes of HCMV CNS disease in an adult and a pediatric T-cell depleted hematopoietic stem cell transplant (HSCT) recipient are reported. In the first case, HCMV encephalitis emerged in the context of simultaneous impairment of the T- and B-cell immunity. Antiviral treatment only reduced viral load in peripheral blood and the patient died. In the second case, an HCMV radiculopathy was observed and antiviral treatment was adjusted on the basis of intrathecal drug level. In addition, donor HCMV-specific cytotoxic T lymphocytes (CTLs) were infused. Viral load in the CNS decreased and the patient recovered from the acute event. In neither case were drug-resistant HCMV variants observed in blood or CNS samples.

CONCLUSIONS

T-cell depleted HSCT appears a predisposing condition for CNS HCMV infection since never observed in other HSCT recipients at our center in the last 15 years. Intensive diagnostic approaches and timely aggressive combination treatments might improve clinical outcome in these patients.

Monitoring and managing viral infections in pediatric renal transplant recipients

Viral infections remain a significant cause of morbidity and mortality following renal transplantation. The pediatric cohort is at high risk of developing virus-related complications due to immunological naiveté and the increased alloreactivity risk that requires maintaining a heavily immunosuppressive environment. Although cytomegalovirus is the most common opportunistic pathogen seen in transplant recipients, numerous other viruses may affect clinical outcome. Recent technological advances and novel antiviral therapy have allowed implementation of viral and immunological monitoring protocols and adoption of prophylactic or preemptive treatment approaches in high-risk groups. These strategies have led to improved viral infection management in the immunocompromised host, with significant impact on outcome. We review the major viral infections seen following kidney transplantation and discuss strategies for preventing and managing these pathogens.

Kinetics of T-lymphocyte subsets and posttransplant opportunistic infections in heart and kidney transplant recipients

BACKGROUND

The potential use of T-lymphocyte measurements as infection risk markers after solid organ transplant has not been fully investigated. We analyzed the kinetics of T-lymphocyte subsets within the first 8 months posttransplant and their correlation with opportunistic infections (OIs) in solid organ transplant recipients.

METHODS

Serial measurement of CD4 and CD8 T cells was performed retrospectively in 48 heart transplant recipients (HTR) and 42 kidney transplant recipients (KTR). Generalized estimating equation models were used to analyze longitudinal data separately for HTR and KTR.

RESULTS

An initial CD4 T-cell drop (at months 1 and 2, in HTR and KTR, respectively) coincided with the peak of OIs. HTR with a low nadir CD4 T-cell count (≤ 200/μL) showed poor CD4 T-cell recovery (175 ± 277 cells/μL at baseline vs 242 ± 99 cells/μL at month 8) and their CD8 T cells increased from 153 ± 194 cells/μL at baseline to 601 ± 399 cells/μL at month 8. KTR with a low nadir CD4 T-cell count (≤ 200/μL) showed a modest CD4 T-cell recovery (138 ± 46 cells/μL at baseline vs. 440 ± 448 cells/μL at month 8), and their CD8 T cells increased from 90 ± 41 cells/μL at baseline to 450 ± 242 cells/μL at month 8. HTR developing OIs had lower CD4 (P<0.001) and CD8 T cells (P=0.001) than those without infections, whereas in KTR the risk for OIs seemed restricted to patients with low CD8 T cells. HTR with OIs had a low CD4/CD8 T-cell ratio, whereas KTR had a high CD4/CD8 T-cell ratio.

CONCLUSIONS

Determination of T-lymphocyte subsets is a simple and effective parameter to identify patients at risk of developing OIs.

Unmanipulated donor lymphocytes for EBV-related PTLD after T-cell depleted HLA-haploidentical transplantation

Epstein-Barr virus (EBV)-related post-transplantation lymphoproliferative disorder (PTLD) is a life-threatening complication in patients given T-cell-depleted hematopoietic stem cell transplantation from an HLA-haploidentical relative (haplo-HSCT). We report the case of a child who developed severe EBV-related PTLD after haplo-HSCT from his mother. Despite receiving the anti-CD20 monoclonal antibody, the patient presented with intestinal obstruction due to huge abdominal lymphadenopathy, hematemesis, and nodulary pulmonary lesions. Histology showed that the lesions were due to CD20-/CD19+ large neoplastic B cells. The patient underwent double intestinal resection with partial abdominal lymphadenectomy and then received 3 monthly doses of donor-derived unmanipulated mononuclear cells. The initial dose of CD3+ cells was 3 10(5)/kg recipient body weight. The 2 additional doses consisted of 5 10(5) CD3+ cells/kg. No sign or symptom attributable to graft-versus-host disease was observed, and the patient completely cleared EBV-related lesions. The child was disease-free for 13 months after the first lymphocyte infusion. This case demonstrates that repeated infusions of controlled numbers of donor CD3+ cells cure EBV-related PTLD in haplo-HSCT without inducing graft-versus-host disease.

Comparison of six different specimen types for Epstein-Barr viral load quantification in peripheral blood of pediatric patients after heart transplantation or after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Epstein-Barr Virus (EBV) a gamma-herpes virus is associated with a spectrum of lymphoid and epithelial malignancies including posttransplant lymphoproliferative disorders (PTLD). EBV-load measurement has been shown to be important for the monitoring of these patients. However, in contrast to the viral quantification of human immunodeficiency virus or human hepatitis C virus, the EBV-load measurement has not been completely standardized as yet.

OBJECTIVES

In this study, we compared the EBV DNA levels in whole blood (WB), plasma, peripheral mononuclear cells (PBMC) and B-cells (BC) in children and adolescents after heart transplantations (HTx) and allogeneic hematopoietic stem cell transplantations (HSCT).

STUDY DESIGN

In a period of 2 years (from May 2007 to May 2009) we collected 547 samples of 96 cardiac transplant recipients and 248 samples of 37 patients who underwent HSCT. For EBV DNA quantification we used a duplex real-time PCR (ABI Prism 7500, Applied Biosystems). Additionally, EBV-load of PBMC and BC were normalized with respect to endogenous cell DNA.

RESULTS

In both patient populations we found no significant difference of test sensitivity for the EBV detection. In PBMC as well as BC, there was a high correlation between the analysis of cells with and without normalization in both populations. Spearman's correlation coefficient ρ between PBMC without and PBMC with normalization was ρ=0.98 (P<0.0001) in patients after HTx and ρ=0.99 (P<0.0001) in patients after HSCT. Correlation between BC with and without normalization was ρ=0.98 (P<0.0001) in patients after HTx and ρ=0.995 (P<0.0001) in patients after HSCT. When comparing the different blood compartments for EBV quantification in both populations, the strongest correlations were found between the EBV DNA levels in WB and PBMC (HTx: ρ=0.93, P<0.0001; HSCT: ρ=0.81, P<0.0001) followed by PBMC and BC (HTx: ρ=0.87, P<0.0001; HSCT: ρ=0.81, P<0.0001) as well as WB and BC (HTx: ρ=0.86, P<0.0001; HSCT: ρ=0.75, P<0.0001). In contrast, the correlation coefficients between plasma and the other blood compartments (WB as well as PBMC or BC) were lower. Six patients developed seven episodes of PTLD (five patients after HTx and one after renal transplantation). Analyzing the different blood compartments, we found that a threshold of WB ≥20,000EBV-copies/ml and plasma ≥1000EBV-copies/ml had the highest sensitivities and specificities (WB: sensitivity 100%, specificity 87% and plasma: sensitivity 88%, specificity 98%).

CONCLUSION

Normalization towards an endogenous control does not seem to be necessary for EBV quantification in peripheral blood. The analysis of whole blood correlates well with B-cells and PBMC. Routine screening of EBV DNA in whole blood appeared to be a useful tool supplemented by EBV-load measurement in plasma to discriminate chronic high EBV-load carrier without risk for PTLD from those who are at risk for PTLD. Values in whole blood higher than 20,000EBV-copies/ml WB and plasma values higher than 1000EBV-copies/ml plasma indicated PTLD in our series.

Post-transplant lymphoproliferative disorders and Epstein-Barr virus DNAemia in a cohort of lung transplant recipients

BACKGROUND

Post-transplant lymphoproliferative disorders (PTLD) are serious complications in lung transplant recipients. No consensus on EBV DNAemia levels predictive of PTLD has been reached. In addition, in many instances EBV DNAemia is determined in patients with suggestive symptoms only.

METHODS

The characteristics of five patients with PTLD as well as the prevalence of EBV DNAmia in a cohort of 137 consecutive patients receiving lung transplantation are described.

RESULTS

Twenty-six out of 137 patients (18.9%) were excluded from the analysis because lost at follow-up or dead from PTLD-independent reasons within three months of transplantation. EBV DNA in peripheral blood mononuclear cells (PBMC) was determined in 83/111 patients (74.8%) because of potential PTLD-related symptoms, while 28 patients (25.2%) showed no symptoms and were not examined. EBV DNAemia was positive in 53/83 patients (63.8%), and negative in 30/83 patients (36.2%). PTLD was diagnosed in five (4.5%) patients at a median time of 270 (range 120-870) days following transplantation. All five PTLD (three large B-cell lymphomas, one Hodgkin lymphoma and one possible pre-neoplastic lesion) were potentially associated with EBV infection. However, only 3/5 patients with PTLD had detectable EBV DNAemia: < 1,000 copies EBV DNA/1 × 10⁵ PBMC in one patient and > 1,000 copies EBV DNA/1 × 10⁵ PBMC in two patients.

CONCLUSION

A systematic multidisciplinary (clinical, radiologic, virologic and histologic) approach is mandatory for the diagnosis and management of PTLD in lung transplant recipients, while monitoring of symptomatic patients only may provide an incomplete or late picture of the clinical problem. In addition, staining for EBV antigens and quantification of EBV DNA in biopsy specimens should always be performed to understand the role of EBV infection in the pathogenesis of PTLD.

Immunotherapy against EBV-lymphoma in recipients of HSCT

Epstein-Barr virus (EBV)-associated lymphoproliferations represent life-threatening complications of hematopoietic stem cell transplantation. In the last decade, immunological therapeutic strategies that allow us to selectively abrogate the origin of lymphoproliferation, namely B-cell compartment or EBV antigen-expressing tumor cells, have significantly reduced treatment-related toxicity while maintaining equal or superior efficacy. A further implementation is the possibility of preventing disease occurrence by delivering immunotherapy in the presymptomatic phase, on the basis of EBV-DNA blood levels. Despite the excellent results, T-cell therapy with EBV-specific cytotoxic T-lymphocytes has but a marginal role in the treatment of these forms. Promising implementations are underway, including logistic solutions to extend T-cell therapy beyond academic centers, delineation of strategies aimed at simplifying/shortening production and targeting immune evasion mechanisms exerted by tumor cells.

T-cell therapy for EBV-associated nasopharyngeal carcinoma: preparative lymphodepleting chemotherapy does not improve clinical results

BACKGROUND

We and others have demonstrated that adoptive cell therapy with Epstein-Barr virus (EBV)-specific autologous cytotoxic T lymphocytes (CTLs) may control disease progression in patients with EBV-associated nasopharyngeal carcinoma (NPC). With the aim of favoring in vivo T-cell expansion, we optimized our cell therapy approach by administering higher doses of EBV-specific CTLs, following lymphodepleting chemotherapy.

PATIENTS AND METHODS

Eleven patients with EBV-related NPC in whom conventional treatment failed have been enrolled. Patients received nonmyeloablative lymphodepleting chemotherapy consisting of cyclophosphamide and fludarabine. Two doses of autologous EBV-specific CTLs were subsequently infused, 2 weeks apart. Study end points were feasibility and clinical outcome.

RESULTS

All patients enrolled completed the treatment and were assessable for analysis. The median dose of CTLs per infusion was 3.7 × 10(8). Therapy was well tolerated, with no severe adverse events ascribable to either chemotherapy or cell therapy. Disease control (defined as either tumor regression or disease stabilization lasting >4 months) was obtained in 6 of 11 patients, in keeping with previously published results.

CONCLUSIONS

Our data confirm that EBV-specific CTL therapy is safe and associated with antitumor activity in patients with advanced NPC. The use of lymphodepleting chemotherapy before high-dose CTL infusion did not enhance the clinical benefit observed in our previous series.

Measurement of Epstein-Barr virus DNA load using a novel quantification standard containing two EBV DNA targets and SYBR Green I dye

Background

Reactivation of Epstein-Barr virus (EBV) infection may cause serious, life-threatening complications in immunocompromised individuals. EBV DNA is often detected in EBV-associated disease states, with viral load believed to be a reflection of virus activity. Two separate real-time quantitative polymerase chain reaction (QPCR) assays using SYBR Green I dye and a single quantification standard containing two EBV genes, Epstein-Barr nuclear antigen-1 (EBNA-1) and BamHI fragment H rightward open reading frame-1 (BHRF-1), were developed to detect and measure absolute EBV DNA load in patients with various EBV-associated diseases. EBV DNA loads and viral capsid antigen (VCA) IgG antibody titres were also quantified on a population sample.

Results

EBV DNA was measurable in ethylenediaminetetraacetic acid (EDTA) whole blood, peripheral blood mononuclear cells (PBMCs), plasma and cerebrospinal fluid (CSF) samples. EBV DNA loads were detectable from 8.0 × 10² to 1.3 × 10⁸ copies/ml in post-transplant lymphoproliferative disease (n = 5), 1.5 × 10³ to 2.0 × 10⁵ copies/ml in infectious mononucleosis (n = 7), 7.5 × 10⁴ to 1.1 × 10⁵ copies/ml in EBV-associated haemophagocytic syndrome (n = 1), 2.0 × 10² to 5.6 × 10³ copies/ml in HIV-infected patients (n = 12), and 2.0 × 10² to 9.1 × 10⁴ copies/ml in the population sample (n = 218). EBNA-1 and BHRF-1 DNA were detected in 11.0% and 21.6% of the population sample respectively. There was a modest correlation between VCA IgG antibody titre and BHRF-1 DNA load (rho = 0.13, p = 0.05) but not EBNA-1 DNA load (rho = 0.11, p = 0.11).

Conclusion

Two sensitive and specific real-time PCR assays using SYBR Green I dye and a single quantification standard containing two EBV DNA targets, were developed for the detection and measurement of EBV DNA load in a variety of clinical samples. These assays have application in the investigation of EBV-related illnesses in immunocompromised individuals.

Epstein-barr virus related lymphoproliferations after stem cell transplantation

Epstein-Barr virus related lymphoproliferative disorders are a rare but potentially fatal complication of allogeneic stem cell transplantation with an incidence of 1–3% and occurring within 6 months after transplantation. The most relevant risk factors include the use of in vivo T-cell depletion with antithymocyte globulin, HLA disparities between donor and recipient, donor type, splenectomy etc. The higher the numbers of risk factors the higher the risk of developing Epstein-Barr virus related lymphoproliferative disorders. Monitoring EBV viremia after transplantation is of value and it should be applied to high risk patients since it allows pre-emptive therapy initiation at specified threshold values and early treatment. This strategy might reduce mortality which was >80% prior to the implementation of anti-EBV therapy. Treatment of EBV-LPD after allogeneic SCT may consist of anti-B-cell therapy (rituximab), adoptive T-cell immunotherapy or both. Rituximab treatment should be considered the first treatment option, preferably guided by intensive monitoring of EBV DNA while reduction of immunosuppression should be carefully evaluated for the risk of graft versus host disease.