[Chronic active Epstein-Barr virus infection with multiple vascular lesions successfully treated by cord blood transplantation].

An 18-year-old woman presented with fever and liver dysfunction. Computed tomography showed lymphadenopathy, hepatosplenomegaly, and vascular lesions such as aneurysms and irregularities at multiple arteries, including coronary arteries. Based on the high copy number of Epstein-Barr virus (EBV)-DNA in the peripheral blood, EBV-infected CD4+T cells, and the proliferation of EBER-positive cells in the bone marrow, chronic active EBV infection (CAEBV) was diagnosed. Although the fever and liver dysfunction improved as a result of the initial immunosuppressive therapy and multiagent chemotherapy, EBV-DNA remained high. Moreover, she experienced repeated episodes of angina pectoris due to coronary arterial lesions. Therefore, cord blood transplantation was performed after reduced-intensity conditioning. EBV-DNA decreased quickly after initiating the conditioning and became undetectable at day 7 after the transplant. Vascular lesions did not progress after the transplant, and the patient's angina pectoris resolved. At 2.5 years after the transplant, she is alive without disease recurrence. The prognosis of CAEBV with vascular lesions is especially poor. Although the indication for allogeneic hematopoietic stem cell transplantation (HSCT) is difficult to determine in such cases, the clinical course of our case suggests that allogenic HSCT could be safely performed under appropriate management and could successfully control not only CAEBV but also vascular lesions.

Evaluation of the immune function assay in pediatric living donor liver transplantation.

The immune function (ImmuKnow) assay is a measure of cell-mediated immunity based on the peripheral CD4+ T cell ATP activity. The efficacy of ImmuKnow in pediatric LDLT is not well documented. The aim of this study was to assess the correlations between the ImmuKnow and the clinical status in pediatric LDLT recipients. A total of 716 blood samples were obtained from 60 pediatric LDLT recipients (one month to 16 yr of age). The recipient's status was classified as follows: stable, infection, or rejection. The ImmuKnow values in the pediatric LDLT recipients with a clinically stable status had a lower immune response (IQR 85-297 ATP ng/mL) than that previously reported in adults. Meanwhile, the ImmuKnow values of the stable patients were not correlated with age. Furthermore, a significant difference was found in the ImmuKnow values between the bacterial or fungal infection and stable groups, but not between the CMV or EBV infection and stable groups. The ImmuKnow levels in the pediatric LDLT were lower than those observed in the adult LDLT. The proposed reference value is between 85 and 297 ATP ng/mL in pediatric LDLT recipients. We conclude that the ImmuKnow assay could be helpful for monitoring pediatric LDLT recipients with bacterial or fungal infections.

Novel mouse xenograft models reveal a critical role of CD4+ T cells in the proliferation of EBV-infected T and NK cells.

Epstein-Barr virus (EBV), a ubiquitous B-lymphotropic herpesvirus, ectopically infects T or NK cells to cause severe diseases of unknown pathogenesis, including chronic active EBV infection (CAEBV) and EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH). We developed xenograft models of CAEBV and EBV-HLH by transplanting patients' PBMC to immunodeficient mice of the NOD/Shi-scid/IL-2Rγ(null) strain. In these models, EBV-infected T, NK, or B cells proliferated systemically and reproduced histological characteristics of the two diseases. Analysis of the TCR repertoire expression revealed that identical predominant EBV-infected T-cell clones proliferated in patients and corresponding mice transplanted with their PBMC. Expression of the EBV nuclear antigen 1 (EBNA1), the latent membrane protein 1 (LMP1), and LMP2, but not EBNA2, in the engrafted cells is consistent with the latency II program of EBV gene expression known in CAEBV. High levels of human cytokines, including IL-8, IFN-γ, and RANTES, were detected in the peripheral blood of the model mice, mirroring hypercytokinemia characteristic to both CAEBV and EBV-HLH. Transplantation of individual immunophenotypic subsets isolated from patients' PBMC as well as that of various combinations of these subsets revealed a critical role of CD4+ T cells in the engraftment of EBV-infected T and NK cells. In accordance with this finding, in vivo depletion of CD4+ T cells by the administration of the OKT4 antibody following transplantation of PBMC prevented the engraftment of EBV-infected T and NK cells. This is the first report of animal models of CAEBV and EBV-HLH that are expected to be useful tools in the development of novel therapeutic strategies for the treatment of the diseases.

Effective control of Epstein-Barr virus infection following pediatric liver transplantation by monitoring of viral DNA load and lymphocyte surface markers.

EBV-associated PTLD is a serious complication of liver transplantation. We performed periodical molecular EBV monitoring in 140 consecutive pediatric patients who had living-related liver transplantation in the National Center for Child Health and Development, Tokyo. Sixty-three of the 140 patients showed elevation of EBV DNA level to >10(2) copies/µg DNA and were further examined immunologically by flow cytometry, and the dose of tacrolimus and/or cyclosporine A was adjusted according to the results. The decrease in CD4/CD8 ratio and the increase in the number of HLA-DR(+) CD8(+) cells were observed in parallel with the decrease in EBV DNA load and in the number of CD19(+) CD23(+) cells following the reduction in immunosuppressive drugs. Analysis with HLA tetramers in a patient demonstrated a dramatic increase in the number of CD8(+) T cells specific to the EBV latent protein LMP2 accompanying the decline of EBV DNA load, suggesting that T cells of this specificity were actually involved in the control of EBV infection. No clinically apparent PTLD has developed in the 140 recipients, suggesting that our program of EBV control by molecular EBV monitoring coupled with lymphocyte phenotype analyses is effective in controlling EBV infection in pediatric liver transplant recipients.

Antineoplastic and anti-inflammatory effects of bortezomib on systemic chronic active EBV infection.

Systemic chronic active Epstein-Barr virus (EBV; sCAEBV) infection, T- and natural killer (NK)-cell type (sCAEBV), is a fatal disorder accompanied by persisting inflammation harboring clonal proliferation of EBV-infected T or NK cells. Today's chemotherapy is insufficient to resolve disease activity and to rid infected cells of sCAEBV. The currently established treatment strategy for eradicating infected cells is allogeneic hematopoietic stem cell transplantation. In this study, we focused on the effects of proteasome inhibitor bortezomib on the disease. Bortezomib suppressed survival and induced apoptosis of EBV+ T- or NK-cell lines and peripheral mononuclear cells containing EBV-infected T or NK cells of sCAEBV patients. Bortezomib enhanced binding immunoglobulin protein/78-kDa glucose-regulated protein (Bip/GRP78) expression induced by endoplasmic reticulum stress and activated apoptosis-promoting molecules JNK and p38 in the cell lines. Bortezomib suppressed the activation of survival-promoting molecule NF-κB, which was constitutively activated in EBV+ T- or NK-cell lines. Furthermore, quantitative reverse transcription-polymerase chain reaction demonstrated that bortezomib suppressed messenger RNA expression of proinflammatory cytokines tumor necrosis factor α (TNF-α) and interferon γ (IFN-γ) in EBV+ T or NK cells from the patients. Finally, we examined the effects of bortezomib using xenograft models of sCAEBV generated by IV injection of patients' cells. The intraperitoneal administration of bortezomib significantly reduced EBV-DNA load in peripheral blood and the infiltration of EBV-infected cells in the models' livers. Moreover, the serum concentration of TNF-α and IFN-γ decreased after bortezomib treatment to the models. Our findings will be translated into the treatment of sCAEBV not only to reduce the number of tumor cells but also to suppress inflammation.

Cellular immunotherapy with ex vivo expanded cord blood T cells in a humanized mouse model of EBV-associated lymphoproliferative disease.

BACKGROUND: Donor lymphocyte infusion is not feasible in recipients of cord blood transplantation. AIM: We investigated whether infusion of T cells expanded from cord blood is effective in the treatment of model mice of Epstein-Barr virus (EBV)-associated lymphoproliferative disease (LPD). MATERIALS & METHODS: Humanized mice with reconstituted human immune system were prepared and LPD was induced by inoculating EBV intravenously. T cells were expanded from the same sample of cord blood as used for generation of humanized mice and infused to EBV-infected humanized mice. RESULTS: Mice treated with expanded cord blood T cells lived significantly longer than control mice (p = 0.036). CONCLUSION: Infusion of T cells expanded from cord blood was effective in the treatment of model mice for EBV-associated LPD.