EBV-associated post-transplantation B-cell lymphoproliferative disorder following allogenic stem cell transplantation for acute lymphoblastic leukaemia: tumor regression after reduction of immunosuppression--a case report

Successful treatment of polymorphic post-transplant lymphoproliferative disorder after allo-HSCT with reduction of immunosuppression

Post-transplant lymphoproliferative disorder (PTLD) is a life-threatening complication for recipients of solid organ transplantation (SOT) and allogeneic hematopoietic stem cell transplantation (allo-HSCT). In SOT recipients, who previously have a normal immune system that has been immunosuppressed, reduction of immunosuppression (RI) shows favorable outcome. However, in HSCT recipients, who have been profoundly immunosuppressed and for whom the tempo of immune reconstitution cannot be fast enough to eliminate the lymphoproliferative process, RI is ineffective in most patients. Therefore, cases of tumor regression via RI alone are rare in the setting of HSCT. We present a case of 26-year-old female developing a polymorphic B-cell PTLD 4 months after receiving allo-HSCT for T cell lymphoblastic lymphoma. RI alone led to regression of the nasopharyngeal tumor, and no sign or evidence of graft-versus-host disease (GVHD) after RI was observed. The general condition of this patient was quite well just before we submitted our draft. To our knowledge, this is the first case that tumor of PTLD regressed upon RI alone with a favorable prognosis and without any evidence of GVHD and relapse of PTLD after RI therapy in the setting of HSCT, which justify the possible advantage of RI alone for low-risk patients.

The effect of Epstein-Barr virus Latent Membrane Protein 2 expression on the kinetics of early B cell infection

Infection of human B cells with wild-type Epstein-Barr virus (EBV) in vitro leads to activation and proliferation that result in efficient production of lymphoblastoid cell lines (LCLs). Latent Membrane Protein 2 (LMP2) is expressed early after infection and previous research has suggested a possible role in this process. Therefore, we generated recombinant EBV with knockouts of either or both protein isoforms, LMP2A and LMP2B (Δ2A, Δ2B, Δ2A/Δ2B) to study the effect of LMP2 in early B cell infection. Infection of B cells with Δ2A and Δ2A/Δ2B viruses led to a marked decrease in activation and proliferation relative to wild-type (wt) viruses, and resulted in higher percentages of apoptotic B cells. Δ2B virus infection showed activation levels comparable to wt, but fewer numbers of proliferating B cells. Early B cell infection with wt, Δ2A and Δ2B viruses did not result in changes in latent gene expression, with the exception of elevated LMP2B transcript in Δ2A virus infection. Infection with Δ2A and Δ2B viruses did not affect viral latency, determined by changes in LMP1/Zebra expression following BCR stimulation. However, BCR stimulation of Δ2A/Δ2B cells resulted in decreased LMP1 expression, which suggests loss of stability in viral latency. Long-term outgrowth assays revealed that LMP2A, but not LMP2B, is critical for efficient long-term growth of B cells in vitro. The lowest levels of activation, proliferation, and LCL formation were observed when both isoforms were deleted. These results suggest that LMP2A appears to be critical for efficient activation, proliferation and survival of EBV-infected B cells at early times after infection, which impacts the efficient long-term growth of B cells in culture. In contrast, LMP2B did not appear to play a significant role in these processes, and long-term growth of infected B cells was not affected by the absence of this protein.

Inhibitory activities of microalgal extracts against Epstein-Barr virus DNA release from lymphoblastoid cells

This study aimed to assess the inhibitory activities of methanol extracts from the microalgae Ankistrodesmus convolutus, Synechococcus elongatus, and Spirulina platensis against Epstein-Barr virus (EBV) in three Burkitt's lymphoma (BL) cell lines, namely Akata, B95-8, and P3HR-1. The antiviral activity was assessed by quantifying the cell-free EBV DNA using real-time polymerase chain reaction (PCR) technique. The methanol extracts from Ankistrodesmus convolutus and Synechococcus elongatus displayed low cytotoxicity and potent effect in reducing cell-free EBV DNA (EC(50)<0.01 µg/ml) with a high therapeutic index (>28000). After fractionation by column chromatography, the fraction from Synechococcus elongatus (SEF1) reduced the cell-free EBV DNA most effectively (EC(50)=2.9 µg/ml, therapeutic index>69). Upon further fractionation by high performance liquid chromatography (HPLC), the sub-fraction SEF1'a was most active in reducing the cell-free EBV DNA (EC(50)=1.38 µg/ml, therapeutic index>14.5). This study suggests that microalgae could be a potential source of antiviral compounds that can be used against EBV.

Inflammation in gastric adenocarcinoma of the cardia: how do EBV infection, Her2 amplification and cancer progression influence tumor-infiltrating lymphocytes?

Tumor-infiltrating lymphocytes (TILs) in gastric adenocarcinoma show a strong compartmentalization with high numbers of lymphocytes in the stroma and low intraepithelial lymphocyte counts. Our previous study has shown stromal regulatory T cells (Treg) to be associated with a beneficial outcome in intestinal type cancer of the cardia. We undertook the present study to further evaluate the immunogenic and inflammatory environment in intestinal-type gastric adenocarcinoma of the cardia. We assessed CXCR3 expression, Epstein-Barr virus (EBV) status, Her2/ERBB2 status and overexpression/amplification using tissue microarrays (immunohistochemistry and in situ hybridization) of 52 patients. The data were correlated to different TIL subset counts (CD3, CD8, GranzymeB, FoxP3 and CD20) and to infiltrating histiocytes (CD68) both in the tumor and the surrounding stromal tissue that were reported earlier. Her2/ERBB2 overexpression/amplification showed no correlation to tumor stage. Moreover, for the first time, we show here that Her2/ERBB2 overexpression/amplification has no correlation to overall or subset-specific TIL infiltration. EBV infection was seen in four cases and showed a strong association with intratumoral CD8(+) T cell infiltration as well as a moderate correlation to stromal CD8(+) T cell accumulation. Intratumoral CD8(+) T cell infiltration was significantly correlated to intratumoral FoxP3(+) Treg infiltration, and to a lesser extent, to stromal FoxP3(+) Treg counts. Stromal CXCR3(+) T cell infiltration showed an inverse correlation to T category. This highlights the importance of stromal immune processes for cancer growth and suggests a subversion of Th1 immunoresponse in cancer progression and underlines the important role of inflammation for early carcinogenesis.