Epstein-Barr virus-associated hemophagocytic syndrome and fatal infectious mononucleosis

L-DEP regimen is effective as an initial therapy for adult EBV-HLH

We performed a single-center, prospective trial to investigate the efficacy of PEG- asparaginase combined with liposomal doxorubicin, etoposide, and methylprednisolone (L-DEP) as an initial therapy for Epstein-Barr virus driven hemophagocytic lymphohistiocytosis (EBV-HLH). None of the patients received any chemotherapy after the diagnosis of EBV-HLH between September 2019 and September 2021. The efficacy was evaluated 2 weeks and 4 weeks after initiating L-DEP primary therapy. Forty-seven eligible patients with EBV-HLH were enrolled. The overall response rate (ORR) was 80.9% (38/47, 12 in clinical CR, 26 in clinical PR) at 2 weeks after the L-DEP regimen; at 4 weeks, the ORR was 75.6% (34/45, 21 in clinical CR, 13 in clinical PR). EBV-DNA loads in blood and plasma were significantly decreased 2 and 4 weeks after the L-DEP regimen (P < 0.001). Ferritin, soluble CD25 (sCD25), triglycerides (TGs), and ultrasonic spleen longitude, and thickness were all decreased significantly 2 and 4 weeks after the L-DEP regimen (P < 0.001). Thus, the L-DEP regimen is an effective initial therapy for EBV-HLH. However, the L-DEP regimen was poor in terms of long-term prognosis and that allo-HSCT should be received as soon as possible once a complete response is achieved.

Clinical analysis and a novel risk predictive nomogram for 155 adult patients with hemophagocytic lymphohistiocytosis

Recently, more and more attention has been paid on adult hemophagocytic lymphohistiocytosis (HLH), a disease with complicated symptoms and high mortality. In order to analyze the clinical characteristics and prediction risk factors of mortality, we designed a retrospective study with 1-year follow-up and included 155 patients admitted to Tongji Hospital diagnosed as HLH. One hundred seven patients formed the training cohort for nomogram development, and 48 patients formed the validation cohort to confirm the model's performance. All patients' clinical characteristics, laboratory results, medical records, and prognosis were analyzed. Among all the 107 patients in the training cohort, 46 were male and 61 were female, with the median age of 49.0 (IQR 31.0-63.0). The 1-year mortality rate was 43.9% (47/107) and 45.8% (22/48) in the training and validation cohort, respectively. And further multivariate logistic regression analysis in the training cohort showed that male (odds ratio 5.534, 95% CI 1.507-20.318, p = 0.010), altered mental status (11.876, 1.882-74.947, p = 0.008), serum ferritin ≥ 31,381 μg/L (8.273, 1.855-36.883, p = 0.006), and IL-6 ≥ 18.59 pg/mL (19.446, 1.527-247.642, p = 0.022) were independent risk factor of mortality. A nomogram included the four prediction factors mentioned above was also tabled to help clinicians evaluate the probability of poor outcome. Area under the receiver operating characteristic curve (AUROC) analysis, calibration curves, and decision curve analysis (DCA) certify the accuracy and the clinical usefulness of the nomogram. Our research reveals that male, altered mental status, serum ferritin ≥ 31,381 µg/L, and IL-6 ≥ 18.59 pg/mL are four independent predictors for poor prognosis. Doctors should pay more attention to patients with altered mental status, high serum ferritin, and IL-6 level, who have a higher risk of death.

Severe Fever with Thrombocytopenia Syndrome Phlebovirus causes lethal viral hemorrhagic fever in cats

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging hemorrhagic fever caused by the SFTS phlebovirus (SFTSV). SFTS patients were first reported in China, followed by Japan and South Korea. In 2017, cats were diagnosed with SFTS for the first time, suggesting that these animals are susceptible to SFTSV. To confirm whether or not cats were indeed susceptible to SFTSV, animal subjects were experimentally infected with SFTSV. Four of the six cats infected with the SPL010 strain of SFTSV died, all showing similar or more severe symptoms than human SFTS patients, such as a fever, leukocytopenia, thrombocytopenia, weight loss, anorexia, jaundice and depression. High levels of SFTSV RNA loads were detected in the serum, eye swab, saliva, rectal swab and urine, indicating a risk of direct human infection from SFTS-infected animals. Histopathologically, acute necrotizing lymphadenitis and hemophagocytosis were prominent in the lymph nodes and spleen. Severe hemorrhaging was observed throughout the gastrointestinal tract. B cell lineage cells with MUM-1 and CD20, but not Pax-5 in the lesions were predominantly infected with SFTSV. The present study demonstrated that cats were highly susceptible to SFTSV. The risk of direct infection from SFTS-infected cats to humans should therefore be considered.

A study of Epstein-Barr virus infection in the Chinese tree shrew(Tupaia belangeri chinensis)

Background

Epstein–Barr virus (EBV) is closely associated with many human diseases, including a variety of deadly human malignant tumours. However, due to the lack of ideal animal models,the biological characteristics of EBV, particularly its function in tumourigenesis, have not been determined. Chinese tree shrews (Tupaia belangeri chinensis), which are similar to primates, have been used to establish a variety of animal models and have recently received much attention. Here, we established tree shrews as a model for EBV infection by intravenous injection.

Methods

Ten tree shrews were inoculated with EBV by intravenous injection,and blood was collected at regular intervals thereafter from the femoral artery or vein to detect EBV markers.

Results

Eight of 10 tree shrews showed evidence of EBV infection. In the 8 EBV-infected tree shrews, EBV copy number increased intermittently or transiently, EBV-related gene expression was detected, and anti-EBV antibodies increased to varying degrees. Macroscopic hepatomegaly was observed in 1 tree shrew, splenomegaly was observed in 4 tree shrews, and enlarged mesenteric lymph nodes were observed in 3 tree shrews. Haematoxylin and eosin (HE) staining showed splenic corpuscle hyperplasia in the spleens of 4 tree shrews and inflammatory cell infiltration of the liver of 1 tree shrew and of the mesenteric lymph nodes of 3 tree shrews. EBER in situ hybridization(ISH) and immunohistochemical (IHC) staining showed that EBER-, LMP1- and EBNA2- positive cells were present in the spleens and mesenteric lymph nodes of some tree shrews. Western blotting (WB) revealed EBNA1-positive cells in the spleens of 4 tree shrews. EBV markers were not detected by HE, EBER-ISH or IHC in the lung or nasopharynx.

Conclusions

These findings suggest that EBV can infect tree shrews via intravenous injection. The presented model offers some advantages for exploring the pathophysiology of EBV infection in humans.

Successful treatment of immediate allogeneic myeloablative hematopoietic stem cell transplantation from a HLA-mismatched sibling donor for active systemic epstein-barr virus-positive T-cell lymphoproliferative disease of childhood following primary acute epstein-barr virus infection

A 22-year-old female was admitted for sustained high fever and diagnosed with systemic Epstein–Barr virus-positive T-cell lymphoproliferative disease. As her clinical course was so aggressive, she immediately underwent allogeneic myeloablative bone marrow transplantation from an HLA-mismatched sibling donor on hospital day 46. The patient has remained in complete remission for 3 years.

Successful treatment of reactive hemophagocytic syndrome by plasmapheresis and high-dose γ-globulin in a patient with systemic lupus erythematosus

Abstract A 31-year-old woman who had been administered corticosteroid and immunosuppressive agents for systemic lupus erythematosus (SLE) without flare-up was diagnosed as having reactive hemophagocytic syndrome (HPS) with severe disseminated intravascular coagulation. The causative underlying disease was uncertain, but it was not the SLE itself. Her fulminant HPS with increased serum ferritin and inflammatory cytokines (sIL-2R, TNF-α, IL-6, and IFN-γ) was successfully treated with plasmapheresis and high-dose γ-globulin therapy.

Lymphoma and cerebral vasculitis in association with X-linked lymphoproliferative disease

Lymphoma is seen in up to 30% of patients with X-linked lymphoproliferative disease (XLP), but cerebral vasculitis related with XLP after cure of Burkitt lymphoma is rarely reported. We describe a case of a 5-year-old boy with XLP who developed cerebral vasculitis two years after cure of Burkitt lymphoma. He had Burkitt lymphoma at the age of 3 years and received chemotherapy (non-Hodgkin's lymphoma-Berlin-Frankfurt-Milan-90 protocol plus rituximab), which induced complete remission over the following two years. At the age of 5 years, the patient first developed headache, vomiting, and then intellectual and motorial retrogression. His condition was not improved after anti-infection, dehydration, or dexamethasone therapy. No tumor cells were found in his cerebrospinal fluid. Magnetic resonance imaging showed multiple non-homogeneous, hypodense masses along the bilateral cortex. Pathology after biopsy revealed hyperplasia of neurogliocytes and vessels, accompanied by lymphocyte infiltration but no tumor cell infiltration. Despite aggressive treatment, his cognition and motor functions deteriorated in response to progressive cerebral changes. The patient is presently in a vegetative state. We present this case to inform clinicians of association between lymphoma and immunodeficiency and explore an optimal treatment for lymphoma patients with compromised immune system.

Innate immune responses against Epstein Barr virus infection

EBV persists life-long in >95% of the human adult population. Whereas it is perfectly immune-controlled in most infected individuals, a minority develops EBV-associated diseases, primarily malignancies of B cell and epithelial cell origin. In recent years, it has become apparent that the course of primary infection determines part of the risk to develop EBV-associated diseases. Particularly, the primary symptomatic EBV infection or IM, which is caused by exaggerated T cell responses, resulting in EBV-induced lymphocytosis, predisposes for EBV-associated diseases. The role of innate immunity in the development of IM remains unknown. Therefore, it is important to understand how the innate immune response to this virus differs between symptomatic and asymptomatic primary EBV infection. Furthermore, the efficiency of innate immune compartments might determine the outcome of primary infection and could explain why some individuals are susceptible to IM. We will discuss these aspects in this review with a focus on intrinsic immunity in EBV-infected B cells, as well as innate immune responses by DCs and NK cells, which constitute promising immune compartments for the understanding of early immune control against EBV and potential targets for EBV-specific immunotherapies.

Hypoalbuminaemia is an independent predictor for hemophagocytic lymphohistiocytosis in childhood Epstein-Barr virus-associated infectious mononucleosis

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a potentially fatal condition in children with Epstein-Barr virus (EBV)-associated infectious mononucleosis (IM). This study aimed to identify commonly available clinical and laboratory predictors that might help clinicians decide to perform the bone marrow and immunological tests for HLH in paediatric EBV-associated IM.

METHODS

A retrospective case-control study of patients aged <18 yr diagnosed with EBV-associated IM and HLH from 1991 to 2010 in a tertiary medical centre was conducted. A diagnosis of HLH was defined as fulfilling the criteria of the guidelines of the HLH-2004 protocol of the Histiocyte Society and consisted of at least evidence of hemophagocytosis in a bone marrow biopsy.

RESULTS

A total of 177 IM and 27 HLH patients were enrolled. The mean age was 5.3 yr with a female-to-male ratio of 1.06. The most common characteristics (>70% of patients) were fever, lymphadenopathy and hepatomegaly. In addition to the diagnostic criteria of HLH including fever, splenomegaly, cytopenia, hyperferritinaemia, hypertriglyceridemia and/or hypofibrinogenaemia, children with HLH had a significantly higher rate of prolonged fever >10 d, hepatomegaly, jaundice, general malaise, elevated aspartate aminotransferase, lactate dehydrogenase, C-reactive protein and hypoalbuminaemia compared to those with IM (all P < 0.01). Multiple logistic regression confirmed that hypoalbuminaemia (OR = 23.1, P = 0.01) was an independent predictor of paediatric HLH, with a high sensitivity (96%) and a good negative likelihood ratio (0.06) in patients with EBV-associated IM.

CONCLUSIONS

Hypoalbuminaemia is a unique characteristic and potentially a valuable predictor for HLH in paediatric EBV-associated IM.

Acute or chronic life-threatening diseases associated with Epstein-Barr virus infection

Infectious mononucleosis (IM) is one of the representative, usually benign, acute diseases associated with primary Epstein-Barr virus (EBV) infection. IM is generally self-limiting and is characterized mostly by transient fever, lymphadenopathy and hepatosplenomegaly. However, very rarely primary EBV infection results in severe or fatal conditions such as hemophagocytic lymphohistiocytosis together with fulminant hepatitis designated as severe or fatal IM or EBV-associated hemophagocytic lymphohistiocytosis alone. In addition, chronic EBV-associated diseases include Burkitt's lymphoma, undifferentiated nasopharyngeal carcinoma, Hodgkin lymphoma, T-cell lymphoproliferative disorder (LPD)/lymphoma, natural killer-cell LPD including leukemia or lymphoma, gastric carcinoma, pyothorax-associated lymphoma and senile B-cell LPD as well as chronic active EBV infection and LPD/lymphoma in patients with immunodeficiency. The number of chronic life-threatening diseases linked to the EBV infection is increasingly reported and many of these diseases have a poor prognosis. This review will focus on the historical, pathogenetic, diagnostic, therapeutic and prophylactic issues of EBV-associated life-threatening diseases.

X-linked lymphoproliferative disease due to SAP/SH2D1A deficiency: a multicenter study on the manifestations, management and outcome of the disease

X-linked lymphoproliferative disease (XLP1) is a rare immunodeficiency characterized by severe immune dysregulation and caused by mutations in the SH2D1A/SAP gene. Clinical manifestations are varied and include hemophagocytic lymphohistiocytosis (HLH), lymphoma and dysgammaglobulinemia, often triggered by Epstein-Barr virus infection. Historical data published before improved treatment regimens shows very poor outcome. We describe a large cohort of 91 genetically defined XLP1 patients collected from centers worldwide and report characteristics and outcome data for 43 patients receiving hematopoietic stem cell transplant (HSCT) and 48 untransplanted patients. The advent of better treatment strategies for HLH and malignancy has greatly reduced mortality for these patients, but HLH still remains the most severe feature of XLP1. Survival after allogeneic HSCT is 81.4% with good immune reconstitution in the large majority of patients and little evidence of posttransplant lymphoproliferative disease. However, survival falls to 50% in patients with HLH as a feature of disease. Untransplanted patients have an overall survival of 62.5% with the majority on immunoglobulin replacement therapy, but the outcome for those untransplanted after HLH is extremely poor (18.8%). HSCT should be undertaken in all patients with HLH, because outcome without transplant is extremely poor. The outcome of HSCT for other manifestations of XLP1 is very good, and if HSCT is not undertaken immediately, patients must be monitored closely for evidence of disease progression.

Infection of T lymphocytes in Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis in children of non-Asian origin

BACKGROUND

Epstein-Barr virus (EBV) is one of the most frequent triggers of hemophagocytic lymphohistiocytosis (HLH). EBV-associated HLH (EBV-HLH) and ectopic infection of T cells has been particularly described in patients from Far East Asia.

PROCEDURE

In a cohort of 12 children with EBV-HLH treated in Germany, the EB viral load was detected by real-time polymerase chain reaction in plasma and peripheral blood mononuclear cells (PBMC). Virological and clinical data were analyzed retrospectively.

RESULTS

Among the 12 mainly German patients, children with underlying immunodeficiencies as well as otherwise healthy individuals were affected. The clinical course ranged from a steroid-responding to a fatal disease despite intensive treatment. Increased EBV copy numbers in plasma and/or PBMC were found in all patients. Serial measurements reflected the course of the disease. Cell-type specific viral load was determined in seven patients and revealed EBV-infection of T cells in all of them. In contrast to the reported Asian patients a significant viral load was also found in B cells.

CONCLUSIONS

T cell infection appears to be a typical feature of EBV-associated HLH irrespective of patients ethnic background and the clinical course. Evaluation of cell-type specific infection should be considered when targeted therapy is applied.

EBV‐associated haemophagocytic syndrome in a patient with Behçet's disease

We present a case of Epstein-Barr virus (EBV)-associated haemophagocytic syndrome in a patient with Behçet's disease. A 43-year-old man, who had been receiving treatment under the diagnosis of Behçet's disease for recurrent oral ulcers, genital ulcer, ileal ulcer, and arthritis, had been admitted for fever, headache, and nausea developed 3 days ago. Laboratory data showed pancytopaenia, an increase in liver enzymes, lactate dehydrogenase (LDH) and ferritin. Haemophagocytic syndrome was diagnosed from histiocytosis and haemophagocytosis by macrophages, shown in the bone marrow aspiration and biopsy, and in situ hybridization for EBV showed a positive finding. The patient recovered rapidly after steroid therapy. This is the first report of EBV-associated haemophagocytic syndrome developed in a patient with Behçet's disease.

A new animal model for primary and persistent Epstein-Barr virus infection: human EBV-infected rabbit characteristics determined using sequential imaging and pathological analysis

Most adults have persistent Epstein-Barr virus (EBV)-infection. Adolescents and young adults with primary EBV-infection frequently develop infectious mononucleosis. Latent EBV-infection is associated with various diseases, neoplasms, and hematological disorders. In vivo animal models of human EBV infection, such as non-human primates, have had limited success. A new rabbit model for primary human EBV-infection is described in this study. Seven male rabbits inoculated intravenously with EBV were sequentially imaged by ultrasonography and computed tomography, and examined for anti-EBV-VCA titer and EBV-DNA levels in blood. Six rabbits demonstrated transient splenomegaly, increased anti-EBV-VCA titers and/or EBV-DNA in blood. Transient infiltration of some EBER1-positive lymphocytes was observed in biopsied liver tissues. After splenomegaly, two rabbits tested continuously negative, two alternatively positive and negative, and one consistently positive EBV detection in blood for 470 days. One tested negative for both EBV DNA and splenomegaly. On the 14th day, mild to moderate numbers of EBER1-positive lymphocytes expressing LMP1, EBNA2, or ZEBRA infiltrated mainly in enlarged white pulps of two splenectomized materials. These cells included both B and T cells. EBV clonality analysis revealed an oligoclonal pattern. These indicate that EBV-inoculated rabbits exhibiting heterogenous host reactions are a good model for primary and persistent human EBV infection.

Epstein-Barr virus nuclear antigen 3A contains six nuclear-localization signals

The Epstein-Barr nuclear antigen 3A (EBNA3A) is one of only six viral proteins essential for Epstein-Barr virus-induced transformation of primary human B cells in vitro. Viral proteins such as EBNA3A are able to interact with cellular proteins, manipulating various biochemical and signalling pathways to initiate and maintain the transformed state of infected cells. EBNA3A has been reported to have one nuclear-localization signal and is targeted to the nucleus during transformation, where it associates with components of the nuclear matrix. By using enhanced green fluorescent protein-tagged deletion mutants of EBNA3A in combination with site-directed mutagenesis, an additional five functional nuclear-localization signals have been identified in the EBNA3A protein. Two of these (aa 63-66 and 375-381) were computer-predicted, whilst the remaining three (aa 394-398, 573-578 and 598-603) were defined functionally in this study.

Epstein-Barr virus LMP1 inhibits the expression of SAP gene and upregulates Th1 cytokines in the pathogenesis of hemophagocytic syndrome

The primary infection of Epstein-Barr virus (EBV) may result in fatal infectious mononucleosis or hemophagocytic syndrome (HPS) in 2 diseases; that is, X-linked lymphoproliferative disorder (XLP) and hemophagocytic lymphohistiocytosis (HLH). XLP is linked to mutations of the SAP/SH2D1A gene with dysregulated T-cell activation in response to EBV infection. Patients with sporadic HLH, however, usually have no mutation of the SAP/SH2D1A gene, and EBV latent membrane protein-1 (LMP1) can up-regulate Th1 cytokines in EBV-infected T cells. Since both diseases share common manifestations of HPS, it is important to clarify whether a cross-talk exists between signaling lymphocyte activation molecule (SLAM)-associated protein (SAP) and LMP1-mediated pathways to explain the common pathogenesis of HPS. In this study, no mutation of the SAP/SH2D1A gene at exon 2/3 was detected in 7 HLH cases. Interestingly, EBV LMP1 could transcriptionally inhibit the expression of SAP/SH2D1A and activate downstream molecules ERK and interferon-gamma (IFN-gamma). LMP1-mediated SAP/ERK/IFN-gamma signals appear to act via the TNF receptor-associated factor (TRAF)2,5/nuclear factor kappaB (NF-kappaB) pathway, since dominant-negative TRAF2/5 and NF-kappaB inhibitor could rescue SAP expression and downregulate IFN-gamma. Although HLH is genetically distinct from XLP, our data suggest that both diseases share a common signal pathway, through either the mutation or LMP1-mediated suppression of the SAP gene, leading to overt T-cell activation and enhanced Th1 cytokine secretion in response to EBV infection.

Molecular and cellular pathogenesis of X-linked lymphoproliferative disease

X-linked lymphoproliferative disease (XLP) is an inherited immune defect caused by mutations in the Src homology 2 domain-containing gene 1A, which encodes the adapter protein, signaling lymphocytic activation molecule (SLAM)-associated protein (SAP). SAP is expressed in T cells, natural killer (NK) cells, and NKT cells, where it binds to the cytoplasmic domain of the surface receptor SLAM (CD150) and the related receptors, 2B4 (CD244), CD84, Ly9 (CD229), NK-T-B-antigen, and CD2-like receptor-activating cytotoxic T cells. SAP also binds to the Src family tyrosine kinase Fyn and recruits it to SLAM, which leads to the generation of downstream phosphotyrosine signals. While the roles of the SLAM family receptors are only beginning to be understood, experiments suggest that these molecules regulate important aspects of lymphocyte function, such as proliferation, cytokine secretion, cytotoxicity, and antibody production. Thus, in XLP patients who lack functional SAP, the SLAM family receptors may not signal properly. This property likely contributes to the phenotypes of XLP, including fulminant infectious mononucleosis, lymphoma, and hypogammaglobulinemia. Further studies of SAP and the SLAM family receptors will provide insights into XLP and elucidate the signaling events regulating lymphocyte ontogeny and function.

Virological and immunological characteristics of a 19-year-old Japanese female with fatal outcome with Epstein-Barr virus-associated hemophagocytic syndrome

Hemophagocytic syndrome (HPS) is caused by the hyperactivation of T-cells and macrophages. The clinical characteristics associated with this disease result from overproduction of cytokines including interferon-gamma (INF-gamma), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6). HPS presents with fever, liver dysfunction, coagulation abnormalities, pancytopenia, and a benign histiocytic proliferation with prominent hemophagocytosis in bone marrow, lymph node, spleen, and liver. We describe a 19-year-old female with fatal HPS. She had been given corticosteroid every other day for systemic lupus erythematosus (SLE) without flare up. The causative underlying disease was acute primary Epstein-Barr virus (EBV) infection. EBV genomes were detected by the polymerase chain reaction (PCR). To measure the virus load we use a real-time PCR assay to quantify the amount of EBV DNA in peripheral blood lymphocytes, lung, kidney, brain and liver at autopsy. Further in situ hybridisation (ISH) and immunohistochemical studies demonstrated that Epstein-Barr virus encoded small RNA (EBER) was detected in CD8+ T-cells in bone marrow, lung, kidney, brain, liver and spleen. In each organ, mRNA levels of inflammatory cytokines (INF-gamma, TNF-alpha, IL-6) were highly detected compared with beta-Actin mRNA levels. These results suggest that EBV-infected CD8+ T-cells in each organ (peripheral blood lymphocytes, lung, kidney, brain and liver) may have an integral role in the pathophysiology of the HPS.

Hodgkin's lymphoma, Epstein-Barr virus reactivation and fatal haemophagocytic syndrome

Haemophagocytic syndrome is a serious disorder, often related to Epstein-Barr virus (EBV) or other infectious agents. Frequently an underlying immune abnormality or a T-cell lymphoma is present. The combination of haemophagocytosis and Hodgkin's lymphoma seems to be rare. A 70-year-old female with rheumatoid arthritis was admitted with constitutional symptoms, persistent fever, pancytopenia, deranged liver enzymes, lymphadenopathy and splenomegaly. A fatal coagulopathy supervened. The clinical picture and the bone marrow findings indicated a haemophagocytic syndrome and a lymph node biopsy disclosed an EBV-positive Hodgkin's lymphoma. EBV serology pointed at viral reactivation and a high EBV DNA content was detected in serum by real-time quantitative PCR analysis (5.5 x 10(6) copies per mL). The case history is presented and the literature is reviewed.

Acute Respiratory Failure and Cerebral Hemorrhage due to Primary Epstein-Barr Virus Infection

Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus with worldwide distribution. Primary infection with EBV occurs early in life and typically presents as infectious mononucleosis. The usual course of the disease is benign and most patients recover uneventfully. Severe infections are reported particularly in immunocompromised patients. Mild, asymptomatic pneumonitis is reported in about 5-10% of cases of infectious mononucleosis, but severe pneumonitis with hypoxemia is very rare in immunocompetent individuals. We report a young female adolescent in whom an acute EBV infection led to severe bilateral pneumonitis, a systemic inflammatory response and intracerebral bleeding. The clinical course and results of quantitative viral DNA determinations in plasma are presented.

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.

Infectious mononucleosis progressing to fatal malignant lymphoma: a case report and review of the literature

Epstein-Barr virus (EBV) infection is nearly ubiquitous. While most primary EBV infections aremild and self-limited, occasional patients will develop severe complications of infectious mononucleosis (IM). Potentially fatal complications include fulminant hepatic failure, virus associated hemophagocytic syndrome and lymphoproliferative disorders. We report the case of an apparently immunocompetent 21-year-old woman with IM that progressed within weeks from a polyclonal B cell proliferation to a fatal B cell lymphoma.

Epstein-Barr virus-associated acute renal failure: diagnosis, treatment, and follow-up

We retrospectively reviewed our experience of Epstein-Barr virus (EBV)-associated acute renal failure. Of 165 previously healthy children hospitalized with serologically proven primary EBV infection, 8 had acute renal failure, of whom 5 (group A) did not have virus-associated hemophagocytic syndrome (VAHS), while 3 (group B) did have VAHS. All had complications in four or more organ systems. Two patients in group A had renal biopsies showing acute tubulointerstitial nephritis, and the clinical and laboratory findings in the other 3 group A patients were consistent with acute tubulointerstitial nephritis. Acyclovir was used in 1 patient, but she died of hepatic failure and pulmonary hemorrhage. The other 4 spontaneously recovered renal function after supportive care, including hemodialysis in 1 patient. Our experience does not support the routine use of corticosteroids or antiviral agents in these patients. Children in group B had a relatively normal urinalysis. Renal biopsies were not performed, but their presentations were compatible with acute tubular necrosis. We conclude that EBV should be considered as a possible etiological agent in all children presenting with acute renal failure of unknown cause. The diagnosis depends on a high index of suspicion and careful serological evaluation in atypical cases.

Rabbit model for human EBV-associated hemophagocytic syndrome (HPS): sequential autopsy analysis and characterization of IL-2-dependent cell lines established from herpesvirus papio-induced fatal rabbit lymphoproliferative diseases with HPS

Epstein-Barr virus-associated hemophagocytic syndrome (EBV-AHS) is often associated with fatal infectious mononucleosis or T-cell lymphoproliferative diseases (LPD). To elucidate the true nature of fatal LPD observed in Herpesvirus papio (HVP)-induced rabbit hemophagocytosis, reactive or neoplastic, we analyzed sequential development of HVP-induced rabbit LPD and their cell lines. All of the seven Japanese White rabbits inoculated intravenously with HVP died of fatal LPD 18 to 27 days after inoculation. LPD was also accompanied by hemophagocytic syndrome (HPS) in five of these seven rabbits. Sequential autopsy revealed splenomegaly and swollen lymph nodes, often accompanied by bleeding, which developed in the last week. Atypical lymphoid cells infiltrated many organs with a "starry sky" pattern, frequently involving the spleen, lymph nodes, and liver. HVP-small RNA-1 expression in these lymphoid cells was clearly demonstrated by a newly developed in situ hybridization (ISH) system. HVP-ISH of immunomagnetically purified lymphoid cells from spleen or lymph nodes revealed HVP-EBER1+ cells in each CD4+, CD8+, or CD79a+ fraction. Hemophagocytic histiocytosis was observed in the lymph nodes, spleen, bone marrow, and thymus. HVP-DNA was detected in the tissues and peripheral blood from the infected rabbits by PCR or Southern blot analysis. Clonality analysis of HVP-induced LPD by Southern blotting with TCR gene probe revealed polyclonal bands, suggesting polyclonal proliferation. Six IL-2-dependent rabbit T-cell lines were established from transplanted scid mouse tumors from LPD. These showed latency type I/II HVP infection and had normal karyotypes except for one line, and three of them showed tumorigenicity in nude mice. These data suggest that HVP-induced fatal LPD in rabbits is reactive polyclonally in nature.

Clinical features and treatment strategies of Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis

Epstein-Barr virus (EBV) is the major triggering factor producing hemophagocytic syndrome or hemophagocytic lymphohistiocytosis (HLH). In this review, diagnostic problems, clinical and histopathological features, and treatment strategies of EBV-HLH have been described. In patients with EBV-HLH, the EBV-infected T cells or natural killer (NK) cells are mostly mono- or oligo-clonally proliferating, where hypercytokinemia plays a major role and causes hemophagocytosis, cellular damage and dysfunction of various organs. Although the majority of EBV-HLH cases develop in apparently immunocompetent children and adolescents, it also occurs in association with infectious mononucleosis, chronic active EBV infection, familial HLH, X-linked lymphoproliferative disease, lymphoproliferative disease like peripheral T-cell lymphoma and NK cell leukemia. In terms of treatment, special therapeutic measures are required to control the cytokine storm generated by EBV and to suppress proliferating EBV-genome-containing cells, because the clinical courses are often fulminant and result in a poor outcome.

Low-dose chemotherapy for children with post-transplant lymphoproliferative disease

Children are at higher risk for developing post-transplant lymphoproliferative disease (PTLD) than adults. Successful treatment of PTLD following solid organ transplant is a therapeutic challenge due to the patients' increased toxicity from chemotherapy, increased susceptibility to life-threatening infections, and the necessity to maintain the allograft. Patients who do not tolerate reduction of immune suppression (i.e., graft rejection), or have PTLD that does not respond to immune suppression reduction, require more aggressive therapy and have a much poorer prognosis. We report 39 children with PTLD who failed reduction of immune suppression and were treated with a low-dose chemotherapy regimen of cyclophosphamide (600 mg/m2) and prednisone (2 mg/kg per day for 5 days) given every 3 weeks for 6 cycles. The complete remission rate was 82%. Graft survival was 90%. Relapse rate was 22%, with late-onset PTLD (> or =2 years from transplant) more likely to relapse. Of the seven patients with relapsed PTLD, four were salvaged with "conventional" non-Hodgkin's lymphoma chemotherapy. The overall 1-year survival for patients treated with low-dose chemotherapy was 86%. The estimated 2-year survival is 73%. This low-dose chemotherapy approach is well tolerated and effective for PTLD in children who fail reduction of immune suppression.

Epstein-Barr virus-associated peripheral T-cell and NK-cell proliferative disease/lymphoma: clinicopathologic, serologic, and molecular analysis

Peripheral T-cell proliferative disease/lymphoma is a group of diseases which exhibits heterogeneity in clinical manifestations, pathological findings and outcomes. They are highly associated with the Epstein-Barr virus (EBV) infection. It is likely that EBV plays an important role in the tumorigenesis. From January 1997 through April 2000, we identified 100 patients. One hundred healthy age- and sex- matched controls were selected. Serologic tests for the EBV infection and the study of EBV genomes in circulating non-T cells (CD3- cells), T cells (CD3+ cells), and T-cell subsets (CD4+ and CD8+ cells) were performed. The main features were prolonged fever, weight loss, hepatosplenomegaly, lymphadenopathy, multiorgan involvement, anemia, and high serum alkaline phosphatase and lactate dehydrogenase. Fifty-one patients had an aggressive course and died; median survival was 21 months. Chemotherapy was not effective in improving survival. Anti-viral capsid antigen-IgG and anti-early antigen-IgG were significantly elevated, whereas there was no significant difference in anti-EBV nuclear antigen. EBV internal repeat-1 region (IR-1) in the peripheral blood CD3+ cells was detected in 65% of the patients but in none of the controls. For the CD3- cells, EBV IR-1 was detected in 88% of the patients and 50% of the controls. Among twenty-five patients whose CD3+ cells were positive for EBV IR-1, 6 (24%) showed EBV IR-1 in only CD4+ cells, 6 (24%) in only CD8+ cells, and 13 (52%) in both CD4+ and CD8+ cells. The 30-bp deletion variant of the EBV latent membrane protein-1 gene was significantly higher in the patients than in the controls. These data support the chronic infective process. The EBV which is dormant in non-T cells may infect T cells and contribute to the pathogenesis of disease in a select group of patients.

Allogeneic bone marrow transplantation for active Epstein-Barr virus-related lymphoproliferative disease and hemophagocytic lymphohistiocytosis in an infant with severe combined immunodeficiency syndrome

A 5-month-old male presented with fever, hepatosplenomegaly, leukocytosis with atypical lymphoblasts, anemia and thrombocytopenia. Severe combined imunodeficiency syndrome (T-, B+, NK+), B lymphoproliferative disease and hemophagocytic lymphohistiocytosis triggered by Epstein-Barr virus (EBV) were diagnosed. As his clinical situation deteriorated rapidly, BMT was performed with unmanipulated marrow stem cells from his EBV-positive HLA-identical sister after conditioning with dexamethasone (1.75 mg/kg/day), cyclophosphamide (114 mg/kg) and etoposide (10 mg/kg), with no immunosuppression given post transplant. Engraftment occurred on day 6 with explosive proliferation of donor CD8(+) T cells. The patient died 3 days later from acute respiratory distress syndrome. Autopsy revealed full donor engraftment and no signs of hemophagocytic lymphohistiocytosis or B lymphoproliferative disease. Thus, transplanted T cells can expand very rapidly within days after BMT and clear EBV lymphoproliferative disease and hemophagocytic lymphohistiocytosis.

Successful allogeneic stem cell transplantation from an unrelated donor for aggressive Epstein-Barr virus-associated clonal T-cell proliferation with hemophagocytosis

We present here a case of aggressive Epstein-Barr virus (EBV)-associated clonal T-cell proliferation with hemophagocytosis that was successfully treated by allogeneic stem cell transplantation using an unrelated donor. A 17-year-old woman was admitted into the hospital with a high fever and liver dysfunction. Laboratory data including bone marrow aspiration revealed hemophagocytic syndrome with proliferation of immature T-lymphoid cells. The clonal proliferation of EBV-infected T cells was confirmed by Southern blot analysis using a terminal-repeat probe from the EBV genome and also by demonstrating T cell-receptor beta gene rearrangement. Intensive immunochemotherapy consisting of cyclosporin A, vincristine, etoposide, and high-dose methylprednisolone did not control the disease and relapse occurred repeatedly. Therefore, during remission after chemotherapy according to the CHOP-E regimen, the patient underwent allogeneic bone marrow transplantation (BMT) from an HLA-matched, unrelated donor. Donor selection was performed with help from the Japanese Association for Marrow Donor Program (JMDP). The patient has remained in good condition without recurrence of disease for 18 months after BMT. Allogeneic BMT is the treatment of choice for aggressive EBV-associated hemophagocytic lymphohistiocytosis even in the case where an HLA-matched sibling donor is not available, especially when the patient is refractory to intensive chemotherapy and/or there is a ready recurrence of disease after conventional therapy.

From Burkitt's lymphoma to chronic active Epstein-Barr virus (EBV) infection: an expanding spectrum of EBV-associated diseases

Epstein-Barr virus (FBV) is one of 8 known human herpesviruses. EBV infection usually occurs in early childhood and is subclinical. However, primary infection in adolescence or adulthood causes infectious mononucleosis in approximately half of infected individuals. Recently, the spectrum of human diseases associated with EBV injection has increased, primarily due to methodological advances in EBV detection. Initially, EBV was isolated from a cultured Burkitt lymphoma cell line, and has been felt to be etiologically linked to the development of Burkitt lymphoma, as well as other human malignancies. This review mainly focuses on pathogenetic mechanisms, many of which remain enigmatic, for the various human diseases, which are considered to be associated with EBV injection.

An animal model for human EBV-associated hemophagocytic syndrome: herpesvirus papio frequently induces fatal lymphoproliferative disorders with hemophagocytic syndrome in rabbits

Epstein-Barr virus-associated hemophagocytic syndrome (EBV-AHS) is often associated with fatal infectious mononucleosis. However, the animal model for EBV-AHS has not been developed. We reported the first animal model for EBV-AHS using rabbits infected with EBV-related herpesvirus of baboon (HVP). Eleven of 13 (85%) rabbits inoculated intravenously with HVP-producing cells developed fatal lymphoproliferative disorders (LPD) between 22 and 105 days after inoculation. LPD was also accompanied by hemophagocytic syndrome (HPS) in nine of these 11 rabbits. The peroral spray of cell-free HVP induced the virus infection with increased anti-EBV-viral capsid antigen-IgG titers in three of five rabbits, and two of these three infected rabbits died of LPD with HPS. Autopsy revealed hepatosplenomegaly and swollen lymph nodes. Atypical lymphoid T cells expressing EBV-encoded small RNA-1 infiltrated diffusely in many organs, frequently involving the lymph nodes, spleen, and liver. Hemophagocytic histiocytosis was observed in the lymph nodes, spleen, bone marrow, and thymus. HVP-DNA was detected in the tissues and peripheral blood from the infected rabbits by polymerase chain reaction or Southern blot analysis. Reverse transcriptase-polymerase chain reaction revealed both HVP-EBNA1 and HVP-EBNA2 transcripts, suggesting latency type III infection. These data indicate that the high rate of rabbit LPD with HPS induction is caused by HVP. This system is useful for studying the pathogenesis, prevention, and treatment of human EBV-AHS.

Intravascular large B-cell lymphoma with bone marrow involvement at presentation and haemophagocytic syndrome: two Western cases in favour of a specific variant

AIMS

To report two cases of an unusual form of intravascular lymphoma, characterized by bone marrow involvement at presentation with haemophagocytic syndrome.

METHODS AND RESULTS

We describe the clinicopathological features of two patients with intravascular lymphoma primarily involving bone marrow. Both patients complained only of fever with pancytopenia and reactive haemophagocytic syndrome. Diagnosis was made on bone marrow examination, which showed large tumour cells of B-cell lineage confined within the lumen of sinuses.

CONCLUSION

These two cases and five previous reports could represent a variant of intravascular lymphoma, characterized by early involvement of bone marrow without dissemination to other organs. This form of intravascular lymphoma, called IVL-HS, seems to be an 'Asian' variant with a high prevalence in Asian people and a very low prevalence in Western countries. At a practical level, bone marrow biopsy may be useful in the diagnosis of intravascular lymphoma when the clinical presentation is restricted to fever of unknown origin with a reactive haemophagocytic syndrome.

Fulminant EBV+ T-cell lymphoproliferative disorder following acute/chronic EBV infection: a distinct clinicopathologic syndrome

This study describes the clinicopathologic features of 5 patients who developed a fulminant Epstein-Barr virus (EBV)-positive clonal T-cell lymphoproliferative disorder (LPD) after acute EBV infection. One additional patient developed a similar disorder in the setting of long-standing chronic active EBV infection. Detailed immunophenotyping, in situ hybridization for EBV early RNA-1 (EBER1) and polymerase chain reaction (PCR) analyses for immunoglobulin (Ig) heavy chain and T-cell receptor (TCR)-gamma gene rearrangements were performed on paraffin-embedded tissue from all patients. In addition, EBV strain typing and detection of the characteristic 30-bp deletion of the latent membrane protein-1 (LMP-1) gene were performed by PCR. Controls included 8 cases of uncomplicated infectious mononucleosis (IM). Patients included 4 males and 2 females with a median age of 18 years (2-37 years). Three patients were Mexican, 2 were white, and 1 was of Asian descent. All presented with fever, hepatosplenomegaly, and pancytopenia; 5 were previously healthy, but had a clinical history of a recent viral-like upper respiratory illness (1 week to 2 months), and 1 patient had documented chronic active EBV infection for 7 years. Serologic data for EBV were incomplete but titers were either negative or only modestly elevated in 3 cases. In 1 case serology was consistent with severe chronic active EBV infection. In the remaining 2 cases serologic studies were not performed. All patients died within 7 days to 8 months of presentation with T-cell LPD. On histologic examination, the liver and spleen showed prominent sinusoidal and portal lymphoid infiltrates of CD3+, βF1+, EBER1+ T cells lacking significant cytologic atypia. Two cases were CD4+, 2 cases were CD8+, and 2 cases had admixed CD4+ and CD8+ cells without clear subset predominance. All were TIA-1+, CD56−. Only rare B cells were noted. Marked erythrophagocytosis was present. Molecular analysis revealed identical T-cell clones in 2 or more sites (liver, spleen, lymph node) in 5 cases. All patients carried type A EBV; 4 cases had wild-type EBV-LMP, and 2 showed the 30-bp deletion. This fulminant T-cell LPD after acute/chronic EBV infection is characterized by hepatosplenomegaly, often without significant lymphadenopathy, fever, liver failure, pancytopenia, and erythrophagocytosis indicative of a hemophagocytic syndrome. EBV serology may be misleading, with lack of elevated titers. The presence of an EBER1+ T-cell infiltrate with scant B cells should alert one to this diagnosis. Although cytologic atypia is minimal, studies for T-cell clonality confirm the diagnosis.

Fulminant EBV+ T-cell lymphoproliferative disorder following acute/chronic EBV infection: a distinct clinicopathologic syndrome

This study describes the clinicopathologic features of 5 patients who developed a fulminant Epstein-Barr virus (EBV)-positive clonal T-cell lymphoproliferative disorder (LPD) after acute EBV infection. One additional patient developed a similar disorder in the setting of long-standing chronic active EBV infection. Detailed immunophenotyping, in situ hybridization for EBV early RNA-1 (EBER1) and polymerase chain reaction (PCR) analyses for immunoglobulin (Ig) heavy chain and T-cell receptor (TCR)-gamma gene rearrangements were performed on paraffin-embedded tissue from all patients. In addition, EBV strain typing and detection of the characteristic 30-bp deletion of the latent membrane protein-1 (LMP-1) gene were performed by PCR. Controls included 8 cases of uncomplicated infectious mononucleosis (IM). Patients included 4 males and 2 females with a median age of 18 years (2-37 years). Three patients were Mexican, 2 were white, and 1 was of Asian descent. All presented with fever, hepatosplenomegaly, and pancytopenia; 5 were previously healthy, but had a clinical history of a recent viral-like upper respiratory illness (1 week to 2 months), and 1 patient had documented chronic active EBV infection for 7 years. Serologic data for EBV were incomplete but titers were either negative or only modestly elevated in 3 cases. In 1 case serology was consistent with severe chronic active EBV infection. In the remaining 2 cases serologic studies were not performed. All patients died within 7 days to 8 months of presentation with T-cell LPD. On histologic examination, the liver and spleen showed prominent sinusoidal and portal lymphoid infiltrates of CD3+, βF1+, EBER1+ T cells lacking significant cytologic atypia. Two cases were CD4+, 2 cases were CD8+, and 2 cases had admixed CD4+ and CD8+ cells without clear subset predominance. All were TIA-1+, CD56−. Only rare B cells were noted. Marked erythrophagocytosis was present. Molecular analysis revealed identical T-cell clones in 2 or more sites (liver, spleen, lymph node) in 5 cases. All patients carried type A EBV; 4 cases had wild-type EBV-LMP, and 2 showed the 30-bp deletion. This fulminant T-cell LPD after acute/chronic EBV infection is characterized by hepatosplenomegaly, often without significant lymphadenopathy, fever, liver failure, pancytopenia, and erythrophagocytosis indicative of a hemophagocytic syndrome. EBV serology may be misleading, with lack of elevated titers. The presence of an EBER1+ T-cell infiltrate with scant B cells should alert one to this diagnosis. Although cytologic atypia is minimal, studies for T-cell clonality confirm the diagnosis.

Lymphadenopathy

Lymphadenopathy can occur in any age group, in symptomatic or asymptomatic patients, and in a single site or at multiple sites. Lymphadenopathy is associated with numerous disorders. An abnormal lymph node may be observed or palpated by the patient, found by a health care worker, or discovered through radiologic evaluation. Lymphadenopathy may be a part of a complex case presentation, or the clinical cause may be straightforward. Patients with potentially curable malignant disorders may have lymphadenopathy as the first sign of their disease. This review of lymphadenopathy summarizes general considerations, discusses which patients might be considered for biopsy, reviews which nodes are most likely to be diagnostic, outlines initial diagnostic considerations on a region-by-region basis, and reviews a broad differential diagnosis for adenopathy.

Haematological associations of Epstein-Barr virus infection

Epstein-Barr virus (EBV) is one of eight human herpesviruses and is ubiquitous. Primary infection with EBV in childhood is generally silent, but often causes overt diseases such as infectious mononucleosis (IM) and lymphoproliferative disorders (LPD). The latter occurs in immunologically compromised individuals. Historically, EBV has been thought to be aetiologically linked to human malignancies such as EBV genome-positive Burkitt's lymphoma (BL) and nasopharyngeal carcinoma (NPC). Furthermore, studies using recent developments in molecular and immunological diagnostic approaches have suggested that this virus has a causative role in a spectrum of human diseases of previously unknown pathogenesis, including chronic active EBV infection syndrome (CAEBV), EBV-related haemophagocytic lymphohistiocytosis (HLH), and certain disorders such as EBV genome-positive T-cell lymphoma, natural killer (NK) cell leukaemia/lymphoma, Hodgkin's disease (HD) and gastric carcinoma. This chapter reviews recent progress regarding EBV-associated diseases.

Haemophagocytic syndrome associated with infections

Haemophagocytic syndromes (HS) are the clinical manifestation of an increased macrophagic activity with haemophagocytosis. Pathophysiology is related to a deregulation of T-lymphocytes and excessive production of cytokines. The main clinicobiological features are fever, hepatosplenomegaly, adenopathies, skin rash, neurological features, cytopenias, hypertriglyceridaemia, hyperferritinaemia and coagulopathy. Diagnosis is based on examination of the bone marrow which shows benign histiocytes actively phagocytosing haemopoietic cells. Acquired HS are mostly associated with an underlying disease such as immunodeficiency, haematological neoplasias and autoimmune diseases. Infection-associated HS was originally described by Risdall in 1979, in viral disease. Since the initial description HS has also been documented in patients with bacterial, parasitic or fungal infections. Epstein-Barr virus (EBV) is the causative agent in most cases. In EBV-associated HS, which sometimes has a fatal course, unregulated T-cell reaction or uncontrolled B-cell proliferation may release cytokines. Management of HS consists of early diagnosis, careful screening for, and prompt treatment of, infections and detection and therapy of any underlying disease. Prognosis of infection-associated haemophagocytic syndrome (IAHS) is better than that in other types of secondary HS. Management of cytokine imbalance should be useful to improve the outcome and reduce the mortality rate in these cases.

Acute complications of Epstein-Barr virus infectious mononucleosis

Infectious mononucleosis caused by Epstein-Barr virus (EBV) usually resolves over a period of weeks or months without sequelae but may occasionally be complicated by a wide variety of neurologic, hematologic, hepatic, respiratory, and psychological complications. The strength of association of EBV with many of these complications remains based on scattered case reports, often using unsophisticated diagnostic tests, and the evidence for causation in many instances is unconvincing. There is little benefit of antiviral treatment of uncomplicated or complicated infectious mononucleosis. Corticosteroids may have a role in hastening resolution of some complications, especially upper airway obstruction and possibly immune-mediated anemia and thrombocytopenia, but should be used judiciously.

A case of adult T-cell lymphoma leukemia with hemophagocytic syndrome

A 62-year-old Japanese woman was admitted to our clinic with virus-associated hemophagocytic syndrome (VAHS) in subcutaneous adult T-cell lymphoma leukemia (ATLL). Bone marrow aspiration showed hypocellularity, histiocytic hyperplasia, and hemophagocytosis. There was serological evidence of chronic cytomegalovirus (CMV) infection. The hemophagocytic syndrome (HPS) initially improved by some treatments, and the patient later experienced remission several times, but the CMV infection persisted. Most cases of non-tumorous HPS in adults are associated with viral or bacterial infection, and underlying diseases in non-tumorous HPS are mostly blood diseases, especially T-cell lymphoma (1, 2), but ATLL is a rare underlying disease in such cases.

Chronic, active Epstein-Barr virus infection

Chronic active Epstein-Barr virus (EBV) infection is an uncommon outcome of EBV infection and may present as a waxing and waning or fulminant syndrome. Unlike acute infectious mononucleosis, wherein EBV establishes lifelong infection and survives by maintaining a delicate balance with the host as a latent infection, in chronic active EBV infection the host-virus balance is disturbed. The mechanisms by which this balance becomes perturbed are likely to be heterogenous and may involve host immune factors, viral factors, or both. A number of subtle immunologic defects have been reported in patients with chronic active EBV infection. Enhanced expression of viral genes has also been noted in some cases. Treatment of chronic active EBV infection has proven difficult, but new modalities including etoposide-based regimens and adoptive transfer of EBV-specific cytotoxic T lymphocytes have shown promise.

Atypical Lymphoproliferative Diseases

This review addresses the clinical presentation, pathology, and therapy of several uncommon lymphoid proliferations. Because these lymphoproliferations span the characteristics of reactive polymorphous proliferations to clonal malignant neoplasms, they are often difficult to diagnose and treat effectively.

In Section I, Dr. Greiner describes the pathology of the spectrum of atypical lymphoid disorders including Castleman's disease, angioimmunoblastic lymphadenopathy, lymphadenopathy in autoimmune diseases, posttransplant lymphoproliferative disorders, and X-linked lymphoproliferative disorder. The relationship to Epstein-Barr virus (EBV) and human herpsesvirus-8 (HHV-8) is discussed, and molecular diagnostic assays and principles for obtaining proper diagnostic evaluation are emphasized.

In Section II, Dr. Armitage presents a practical approach to the management of Castleman's disease. The discussion includes the importance of confirmation of the histological diagnosis and careful staging evaluation, therapeutic options, and the increased risks for infection and lymphoma. The appropriate roles of surgical excision, corticosteroids, and combination chemotherapy are addressed along with alternative strategies such as anti-interleukin-6 and bone marrow transplantation.

In Section III, Dr. Gross reviews the treatment of EBV-associated lymphoproliferative disorders in primary immunodeficiencies and in post-transplant patients. He gives an update on the recent molecular discoveries in X-linked lymphoproliferative disorder. Preliminary results of a phase II trial of low-dose cyclophosphamide in posttransplant lymphoproliferative disorders and the use of GM-CSF as preemptive therapy are presented.

Atypical Lymphoproliferative Diseases

This review addresses the clinical presentation, pathology, and therapy of several uncommon lymphoid proliferations. Because these lymphoproliferations span the characteristics of reactive polymorphous proliferations to clonal malignant neoplasms, they are often difficult to diagnose and treat effectively.

In Section I, Dr. Greiner describes the pathology of the spectrum of atypical lymphoid disorders including Castleman's disease, angioimmunoblastic lymphadenopathy, lymphadenopathy in autoimmune diseases, posttransplant lymphoproliferative disorders, and X-linked lymphoproliferative disorder. The relationship to Epstein-Barr virus (EBV) and human herpsesvirus-8 (HHV-8) is discussed, and molecular diagnostic assays and principles for obtaining proper diagnostic evaluation are emphasized.

In Section II, Dr. Armitage presents a practical approach to the management of Castleman's disease. The discussion includes the importance of confirmation of the histological diagnosis and careful staging evaluation, therapeutic options, and the increased risks for infection and lymphoma. The appropriate roles of surgical excision, corticosteroids, and combination chemotherapy are addressed along with alternative strategies such as anti-interleukin-6 and bone marrow transplantation.

In Section III, Dr. Gross reviews the treatment of EBV-associated lymphoproliferative disorders in primary immunodeficiencies and in post-transplant patients. He gives an update on the recent molecular discoveries in X-linked lymphoproliferative disorder. Preliminary results of a phase II trial of low-dose cyclophosphamide in posttransplant lymphoproliferative disorders and the use of GM-CSF as preemptive therapy are presented.

Antigen-Driven Expansion and Contraction of CD8+-Activated T Cells in Primary EBV Infection

The origin of the increased numbers of CD8+ atypical lymphocytes, expressing activated markers such as HLA-DR or CD45RO, in the peripheral blood of patients with infectious mononucleosis (IM) has been debated. Using a recently developed assay to detect intracellular accumulation of IFN-γ in EBV-reactive T cells by FACS, we have demonstrated that 34–54% of HLA-DR+/CD8+ and 34–60% of CD45RO+/CD8+ T cells in the PBMCs of febrile patients suffering from IM are EBV-specific. The EBV-specific CD8+ T cell counts in the PBMCs of four febrile patients suffering from IM ranged between 2260 and 8200/μl, decreasing to 5.1% and 7.9% of the counts in the first samples over 10 days in two donors. The decline of CD8+ T cell subpopulations, namely HLA-DR+, CD45RO+, and EBV-specific T cells, was in parallel with the drop in the EBV genome load. These data indicate that the Ag-driven expansion of CD8+ T cells and subsequent contraction with the Ag decline in vivo in humans is effective for clearing virus-infected cells with minimal disturbance of the homeostasis of the immune system.

Marked histiocytosis in the portal tract in a patient with reactive hemophagocytic syndrome: An autopsy case

We report an autopsy case of reactive hemophagocytic syndrome with peculiar liver histology. A 71-year-old female was diagnosed as having acute myelogenous leukemia and treated with chemotherapy. During her course, methicillin-resistant Staphylococcus aureus (MRSA) was noted in blood culture and she was diagnosed as having MRSA sepsis. She died of respiratory failure 5 months after the onset of leukemia and 10 days after the MRSA sepsis. Ante-mortem liver function tests were within normal ranges. At autopsy, myeloblastic leukemia cells positive for CD13 were present in the bone marrow and, to a much lesser extent, in the spleen and liver. Numerous histiocytes of a bland appearance with erythrophagocytosis were noted in the bone marrow and spleen. The histiocytes were positive for CD68, but negative for S-100 and lysozymes. In the liver, many histiocytes of bland appearance with erythrophagocytosis and CD68 positivity were present in the portal tracts with no Kupffer cell hyperplasia. There were no hepatocellular degeneration, fatty changes or sinusoidal dilations. We consider that this histiocytosis was associated with MRSA infection and diagnosed this as infection-associated hemophagocytic syndrome. In previously reported cases, hemophagocytosis in hyperplastic Kupffer cells was the main liver change of reactive hemophagocytic syndrome. The present case suggests that marked histiocytosis in portal tracts only may be a main feature of liver changes in reactive hemophagocytic syndrome and that such cases may not show abnormal liver function tests.