EBV load in whole blood correlates with LMP2 gene expression after pediatric heart transplantation or allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Epstein-Barr virus (EBV) is associated with posttransplant lymphoproliferative disease (PTLD), and EBV load measurement is an important tool to monitor transplant patients. Although EBV DNA quantification has high sensitivity to identify patients at risk for PTLD, it lacks specificity. We examined whether EBV gene expression in peripheral B cells can increase specificity or correlates with EBV load. METHODS: Altogether, 220 blood samples were collected from pediatric patients after heart transplantation (HTx, n=57), renal transplantation (n=1), or hematopoietic stem cell transplantation (n=21). In each blood sample, EBV load was quantified in whole blood, plasma, and B cells using qPCR. Additionally EBV gene expression (EBNA2, LMP1, LMP2, and BZLF1) in B cells was analyzed using relative quantitative RT-qPCR. RESULTS: Positive expression of at least one gene was detected in 112 (51%) of 220 samples. Patients with PTLD or chronic high viral loads after solid organ transplantation exhibited no homogeneous EBV gene expression pattern. Expression of LMP2, LMP1, or EBNA2 was only observed when EBV load exceeded 1000 copies/mL. A high correlation between the level of LMP2 expression and EBV load in B cells or whole blood was observed (ρ=0.72 or ρ=0.6, HTx population). CONCLUSION: The analysis of EBV gene expression in peripheral B cells does not provide additional information about patients' risk of developing PTLD. As EBV load in whole blood correlates well with LMP2 gene expression in EBV-infected B cells, EBV DNA quantification in whole blood alone seems to be a sufficient tool to monitor these patients.

Differentiation of EBV-induced post-transplant Hodgkin lymphoma from Hodgkin-like post-transplant lymphoproliferative disease.

The development of lymphomas after SOT is a well-known complication of the immunosuppressive therapy necessary to prevent graft rejection. Epstein-Barr virus plays a central role in the pathogenesis of lymphomas because of its ability to transform infected cells. Differentiating PTLD from malignant lymphomas, especially HL can be challenging. We report on two patients, who developed EBV-associated lymphomas several years after SOT. A histological examination of lymph nodes led to a diagnosis of HL in both patients, who were started on chemotherapy according to current treatment protocols. A rapid and complete remission in one patient prompted us to analyze the expression pattern of EBV-latency genes. In this patient, the EBV expression profile revealed a latency type III suggesting the diagnosis of Hodgkin-like PTLD. The other patient required six courses of chemotherapy plus radiotherapy to reach a complete remission. In his tumor cells, a restricted EBV-latency type II pattern was found, suggesting a diagnosis of classical HL. These two cases demonstrate that in post-transplant lymphomas with histological features of HL, an analysis of the expression pattern of EBV proteins might aid in the differentiation between PTLD and HL.

Time course and frequency of Epstein-Barr virus reactivation after kidney transplantation: linkage to renal allograft rejection.

The onset and frequency of Epstein-Barr virus (EBV) reactivation after kidney transplantation are unknown. By use of quantitative real-time polymerase chain reaction measurements, evidence of early EBV reactivation, occurring within the first week after the initiation of immunosuppressive therapy (median, 3 days), was observed in 13 of 23 patients, of whom 10 subsequently developed rejection episodes after 2-45 days (median, 5 days). By contrast, rejection was only diagnosed in 1 of 10 patients who did not show signs of viral reactivation. We suggest that EBV reactivation may induce a T cell response that, through the phenomenon of allo-cross-reactivity, could play a critical role in graft rejection.

Inhibition of macrophage inflammatory protein-1 alpha production by Epstein-Barr virus.

Infection with Epstein-Barr virus (EBV) exerts substantially immunomodulating activities in vitro and in vivo. In this context, EBV-induced chemokine production and the influence of EBV on this highly redundant system of inflammatory proteins have hardly been investigated. This study analyzed the production of interleukin-8, RANTES, monocyte chemotactic protein-1, and macrophage inflammatory protein-1 alpha (MIP-1 alpha) on EBV infection of peripheral blood mononuclear cells from immune EBV-seropositive (EBV(+)) and noninfected EBV-seronegative (EBV(-)) individuals. EBV failed to induce the production of MIP-1 alpha in EBV(+) as well as EBV(-) individuals, whereas the other chemokines studied were readily expressed. Moreover, EBV completely down-regulated lipopolysaccharide (LPS)- and phytohemagglutinin-induced MIP-1 alpha production up to 4 hours after induction. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of EBV- and LPS-stimulated cultures revealed that EBV inhibited MIP-1 alpha production on the transcriptional level. This effect was abolished by addition of antiglycoprotein (gp)350/220, a monoclonal antibody against EBV's major envelope glycoprotein, which mediates binding of the virus to the EBV receptor, CD21. However, recombinant gp350/220 protein alone did not inhibit the LPS-induced MIP-1 alpha production, indicating that infection of the target cell is indispensable for this effect. In summary, we demonstrate a new immunomodulating activity of EBV on the chemokine system that probably helps the virus to evade the host's immune system favoring lifelong infection.