Lymphomas and microenvironment: Impact on lymphomagenesis. Foreword

CD14-CD10-CD45+HLA-DR-SSC+ neutrophils may be granulocytic myeloid-derived suppressor cell-like cells and relate to disease progression in non-Hodgkin's lymphoma patients

We explored the frequency of CD14-CD10-CD45+HLA-DR-SSC++ neutrophils (CD10- neutrophils) in patients with non-Hodgkin's lymphoma (NHL), and their immunologic characteristics and clinical significance. Patients with NHL who were newly diagnosed (NDP; n = 33), in remission (RMP; n = 28) and relapsed (RLP; n = 29) were included, and 47 volunteers were recruited as healthy controls (HCs). The frequency of CD10- neutrophils in the peripheral blood from HC and patients with NHL was detected. CD10- and CD10+ neutrophils were sorted, and their cytology was analyzed. CD3+ T cells were also isolated and cultured with the autologous CD10- or CD10+ neutrophils, after which the proliferation and death rates of T cells were determined. The levels of arginase-1 (Arg-1) and reactive oxygen species (ROS) in CD10+ or CD10- neutrophils were examined. Few CD10- neutrophils were detected in HCs but were significantly elevated in patients with NHL, especially in NDP and RLP. In addition, CD10- neutrophils in NDP with advanced stage and high risk were markedly higher than those in NDP with limited stage and low risk. In RMP and RLP, the relapse-free survival and overall survival in patients with high CD10- neutrophils were shorter than those with low CD10- neutrophils. CD10- neutrophils from patients with NHL, which mainly consist of immature neutrophils, inhibit T-cell proliferation and facilitate T-cell death. Furthermore, a significant increase was observed in Arg-1 expression, along with an increase to a certain extent in ROS. CD10- neutrophils in patients with NHL have characteristics of myeloid-derived suppressor cells and may be related to disease progression and poor prognosis.

Differences in Epstein-Barr Virus Characteristics and Viral-Related Microenvironment Could Be Responsible for Lymphomagenesis in Children

In Argentina, Epstein-Barr virus (EBV) presence is associated with Hodgkin lymphoma (HL) in patients younger than 10 years, suggesting a relationship between low age of EBV infection and HL. Given that HL is derived from germinal centers (GC), our aim was to compare EBV protein expression and microenvironment markers between pediatric HL patients and EBV+GC in children. Methods: EBV presence and immune cell markers were assessed by in situ hybridization and immunohistochemistry (IHC). Results: Viral latency II pattern was proved in all HL patients and in 81.8% of EBV+ tonsillar GCs. LMP1 and LMP2 co-expression were proved in 45.7% HL cases, but only in 7.7% EBV+ GC in pediatric tonsils. An increase in CD4+, IL10, and CD68+ cells was observed in EBV+ GC. In pediatric HL patients, only the mean of IL10+ cells was statistically higher in EBV+ HL. Conclusions: Our findings point us out to suggest that LMP1 expression may be sufficient to drive neoplastic transformation, that an immune regulatory milieu counteracts cytotoxic environment in EBV-associated Hodgkin lymphoma, and that CD4+ and CD68+ cells may be recruited to act in a local collaborative way to restrict, at least in part, viral-mediated lymphomagenesis in tonsillar GC.

A lymphomagenic role for HIV beyond immune suppression?

Despite the immune reconstitution promoted by combined antiretroviral therapy (cART), lymphomas still represent the most common type of cancer in HIV-infected individuals. Cofactors related to immunodeficiency such as oncogenic viruses, chronic antigenic stimulation, and cytokine overproduction are thought to be the main drivers of HIV lymphomagenesis, although the current scenario does not convincingly explain the still-high incidence of lymphomas and the occurrence of peculiar lymphoma histotypes in HIV-infected patients under cART. Recent findings are challenging the current view of a mainly indirect role of HIV in lymphoma development and support the possibility that HIV may directly contribute to lymphomagenesis. In fact, mechanisms other than immune suppression involve biologic effects mediated by HIV products that are secreted and accumulate in lymphoid tissues, mainly within lymph node germinal centers. Notably, HIV-infected patients with lymphomas, but not those not affected by these tumors, were recently shown to carry HIV p17 protein variants with enhanced B-cell clonogenic activity. HIV p17 protein variants were characterized by the presence of distinct insertions at the C-terminal region of the protein responsible for a structural destabilization and the acquisition of novel biologic properties. These data are changing the current paradigm assuming that HIV is only indirectly related to lymphomagenesis. Furthermore, these recent findings are consistent with a role of HIV as a critical microenvironmental factor promoting lymphoma development and pave the way for further studies that may lead to the design of more effective strategies for an early identification and improved control of lymphomas in the HIV setting.