The tumor microenvironment of classical Hodgkin lymphoma (cHL) is clearly responsible for the maintenance of the malignant Hodgkin-Reed-Sternberg (HRS) cells, and Epstein-Barr virus (EBV) has been shown to play a role in this immune evasion. EBV can increase the migration of CD4(+)CD25(+)FOXP3(+) lymphocytes, named regulatory T cells (Tregs). In this study, we assessed the distribution and biological significance of Tregs in patients with cHL. Tissue microarrays were constructed using diagnostic biopsies available in 130 cHL patients and stained with CD4, CD8, CD25, and FOXP3 antibodies. For the present study, only cHL patients whose histology could be confirmed and EBV association established were studied. From the 130 cHL patients selected for this study, 56 were classified as EBV-related and 74 EBV non-related cHL. There were no association between clinical characteristics and the expression of Tregs. However, higher levels of Tregs correlated with EBV presence on HRS cells (p = 0.02), although it did not influence event-free survival (EFS) and overall survival (p = 0.98 and p = 0.59, respectively). This study demonstrates that Tregs expression correlates with EBV presence in HRS cells and has no impact on survival of patients with cHL. Further studies investigating the mechanisms in which EBV recruits Tregs to the tumor microenvironment will contribute not only to our understanding on the pathogenesis of cHL but also to the development of new therapeutic strategies.

High-performance locally resonant metamaterials represent the next frontier in materials technology due to their extraordinary properties obtained through materials design, enabling a variety of potential applications. the most exceptional feature of locally resonant metamaterials is the subwavelength size of their unit cells, which allows to overcome the limits in wave focusing, imaging and sound/vibration isolation. To respond to the fast evolution of these artificial materials and the increasing need for advanced and exceptional properties, the emergence of a new mechanism for wave mitigation and control consisting in a nonlinear interaction between propagating and evanescent waves has recently been theoretically demonstrated. Here, we present the experimental proof of this phenomenon: the appearance of a subharmonic transmission attenuation zone due to energy exchange induced by autoparametric resonance. these results pave the path to a new generation of nonlinear locally resonant metamaterials. Metamaterials 1, 2 are artificially engineered materials designed to obtain specific, often exotic, properties. Among the wide variety of possible metamaterial properties, the opening of a band gap, which is defined as the frequency range where elasto-acoustic waves cannot propagate, is attracting increasing interest because of its versatile applications 3-5. In particular, a wide and low frequency band gap offers a number of potential applications, such as sound attenuation, super-resolution acoustic imaging, and vibration mitigation. Typical physical phenomena responsible for the band gap opening are Bragg scattering 6,7 , inherent to periodic structures, and local resonance 8 that also promotes band gaps in materials composed of unit cells with subwavelength dimensions. The latter is the focus of the present work. Locally resonant metamaterials operating in the nonlinear regime 9-11 provide even more opportunities for breakthrough applications. Recently, nonlinearities have been exploited in locally resonant granular crystals 12,13 or to obtain logic gates 14 and acoustic diodes 15. Despite of great interest, the number of investigations carried out on the nonlinear dynamic behavior of locally resonant metamaterials exhibiting attenuation frequency ranges is quite limited in comparison with linear ones, also because of the conceptual and modelling difficulties 16-20. Only few works investigated the energy transfer mechanisms induced by the nonlinear coupling between the resonator and the host medium. In some papers 21-24 , the irreversible energy transfer mechanisms are induced by a single purely nonlinear attachment, the so-called nonlinear energy sinks (NES). Only very few papers have considered cases in which nonlinear resonant attachments are densely or periodically distributed in a host material. In this case, two main energy transfer mechanisms can arise. The first one is called inter/intra-modal tunneling and is a well-studied phenomenon in nonlinear wave dynamics. It consists of an energy exchange between t...

In this paper, the transient computational homogenization scheme is extended to allow for nonlinear elastodynamic phenomena. The framework is used to analyze wave propagation in a locally resonant metamaterial containing hyperelastic rubber-coated inclusions. The ability to properly simulate realistic nonlinearities in elasto-acoustic metamaterials constitutes a step forward in metamaterial design as, so far, the literature has focused only on academic nonlinear material models and simple lattice structures. The accuracy and efficiency of the framework are assessed by comparing the results with direct numerical simulations for transient dynamic analysis. It is found that the band gap features are adequately captured. The ability of the framework to perform accurate nonlinear transient dynamic analyses of finite-size structures is also demonstrated, along with the significant computational time savings achieved.

the use of the wave finite element method for passive vibration control of periodic structures.Abstract. In this work, a strategy for passive vibration control of periodic structures is proposed which involves adding a periodic array of simple resonant devices for creating band gaps. It is shown that such band gaps can be generated at low frequencies as opposed to the well known Bragg scattering effects when the wavelengths have to meet the length of the elementary cell of a periodic structure. For computational purposes, the wave finite element (WFE) method is investigated, which provides a straightforward and fast numerical means for identifying band gaps through the analysis of dispersion curves. Also, the WFE method constitutes an efficient and fast numerical means for analyzing the impact of band gaps in the attenuation of the frequency response functions of periodic structures. In order to highlight the relevance of the proposed approach, numerical experiments are carried out on a 1D academic rod and a 3D aircraft fuselage-like structure.

The Tissue Engineering appears with a modern proposal for the treatment of damages or diseases. The study of materials and methods for tissues and organs regeneration by the patient cells culture had been developed on the last years but still couldn’t be used for all different tissues. In this multidisciplinary research field, the present work joins the biodegradability of poly(ε-caprolactone) (PCL) with the osteoconductive properties of β-tricalcium phosphate (β-TCP) in order to create a composite which acts as a temporary support for cell culture without a second surgery to remove the biomaterial. This work evaluates three membranes types, obtained by casting in chloroform, on the biocompatibility and differentiation on mesenquimal stem cells (hMSC). These analyses showed cell viability with the rezasurin method and the alkaline phosphatase activity (ALP). DMA analyses, MEV and OPM were performed.

2286 It is known that major surgery and allogeneic blood transfusion mediate immunosuppression by interfering on cytokine secretion, lymphocyte count and cytotoxic response. However, which cytokines and lymphocyte subpopulations participate in such immunosuppressive state remains poorly understood. Regulatory T cells (Tregs) are suppressive CD4(+) cells with a central role in immunosuppression of trauma victims, cancer patients, and transplant recipients. Several markers have been identified with regulatory properties, such as FOXP3, CTLA-4, GITR and the recently described CD69. Recently, allogeneic blood transfusion has been shown capable of inducing regulatory CD4+FOXP3+ T cells in vitro. Purpose: In this study, we aimed to investigate regulatory CD4+ T cells induction and cytokine profile in transfused and non-transfused surgical patients. Patients and Methods: Thirty-five patients undergoing elective hip replacement were recruited for this study and prospectively evaluated. Blood samples were obtained before surgery (D0) and on days 1 (D1) and 4 (D4) after surgery. Quantification of regulatory T lymphocytes was done by flow cytometry using CD4, CD25, FoxP3, CTLA-4, GITR and CD69, while cytokines (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-17A, TNF-α, IFN-γ and TGF-β) levels were determined by multiplexed immunoassay system. Results: From the 35 patients recruited for this study, 18 (51.4%) received allogeneic non-leukodepleted red cells transfusion during or after surgery. There were no significant differences in clinical or epidemiological characteristics between transfused and non-transfused groups, except for the duration of surgery, being longer in transfused patients (p<0.001). Results of total lymphocyte count and subsets of CD4+ T cells in the 35 patients are summarized in the table: The total lymphocyte count was significantly decreased only in transfused patients. No significant difference was seen in the percentage of CD4+CD25highFoxp3+ T lymphocytes by comparing days D0, D1 and D4. However, a significant increase of CD4+CD25-CD69+ cells was observed by comparing D1 vs. D4 [0.61(0.23–2.69) vs. 2.27 (0.64–4.45); p=0.001] in transfused patients, but not in the group of non-transfused patients [0.36(0.31–0.81) vs. 1.02(0.42–1.52); D1 vs. D4. Similarly, we also detected a significant increase in the number of CD4+GITR+ T cells in the group of transfused patients [D1 vs. D4; 3.12±2.01 vs. 5.19±3.33; p=0.007). Total hip replacement also led to substantial increase of the following cytokines: IL-6 (p<0.001, D0 vs. D1 and p<0.001, D0 vs. D4), IL-8 (p<0.001, D0 vs. D1 and p=0.017, D0 vs. D4), IL-10 (p<0.001, D0 vs. D1). However, no differences regarding cytokines levels were seen comparing groups of transfused and non-transfused patients. Conclusions: This study demonstrated that although allogeneic non-leukodepleted red cells transfusion is associated with decrease of total lymphocyte count following major surgery, there was a significant increase of total CD4+ T lymphocytes with no difference observed in transfused and non-transfused patients. However, a significant increase of CD4+CD25-CD69+ and CD4+GITR+ T lymphocytes was observed in the transfused group on D4, possibly reflecting the late effect of transfusion on induction of these subsets of CD4+ regulatory cells. The increase of pro-inflammatory IL-6, IL-8 and anti-inflammatory IL-10 levels indirectly highlights the imbalance on immune response after surgical trauma. Further studies, with a larger cohort and functional assays, investigating these CD4+ T cells subpopulations following major surgery and the impact of allogeneic non-leukodepleted red cells transfusion on these cells should be addressed. Disclosures: No relevant conflicts of interest to declare.

4778 Cytotoxic T lymphocyte antigen-4 (CTLA-4) is one of the basic antigens involved in immune responses regulation associated with autoimmune diseases and cancer. Its key role in regulating the immune system has made CTLA-4 an attractive target for cancer. Augmentation of the immune response via blockade of CTLA-4 has shown an improvement in survival for patients with metastatic melanoma, which prompted the Food and Drug Administration (FDA) approval of the CTLA-4 function blocking antibody Ipilimumab for this disease. Objective: The aim of the study was to evaluate the surface expression of CTLA-4 on CD4+ T cells in peripheral blood mononuclear cells (PBMC) of patients with classical Hodgkin lymphoma (cHL) at diagnosis and post-treatment and correlate these findings with clinical and epidemiological aspects. Material and Methods: This is an open study and, so far, we included 35 patients from December 2009 to December 2011. Blood was drawn at diagnosis and post-treatment (1 to 4 months after completion of therapy). The T cell phenotype was evaluated by flow cytometry using CD3, CD4, CD8, CTLA-4 and correlated to phenotypic and clinical parameters in uni- and multivariate models pre and post-treatment. Eighteen healthy blood donors volunteers were recruited as controls. In this study, only cHL patients whose histology could be confirmed and Epstein-Barr (EBV) association established were studied. All patients were HIV negative and received ABVD chemotherapy protocol and radiotherapy if necessary. Three patients relapsed, and blood was also drawn at this time. Results: From the 35 cHL patients, 17 were EBV related and 18 EBV non-related. The percentage of CD4+ T cells with CTLA-4 surface expression was significantly increased in patients with cHL at diagnosis compared with healthy controls (median 7.36 vs 2.73; P<0.001). Additionally, CD4+CTLA-4+ T lymphocytes significantly decreased following treatment and complete response (7.36 vs 4.53; p=0.008), with values similar to healthy controls (4.53 vs 2.73; p=0.07). Interestingly, CD4+CTLA-4+ T lymphocytes on relapse were significantly different from post-treatment values and similar to pre treatment. There was no difference on CD4+CTLA-4+ T lymphocytes in the EBV related and non-related cHL patients. Regarding patient's baseline characteristics, CD4+CTLA-4+ T lymphocytes strongly correlated with erythrocyte sedimentation rate (ESR) values (r=0.67; p=0.002). Conclusions: We showed that CD4+CTLA-4+ T lymphocytes are increased in Brazilian cHL patients at diagnosis compared with post-treatment values and healthy controls. These results suggest a role of CTLA-4 on Hodgkin lymphomagenesis, possibly negatively regulating host anti-tumor immune response. The promising immunotherapy regimen targeting CTLA-4 might be beneficial in classical Hodgkin lymphoma. Disclosures: No relevant conflicts of interest to declare.

Over the last two decades, metamaterials have attracted a high number of researches motivated by the possibility of designing structures capable of manipulating wave propagation. The basic mechanism underlying the behavior of mechanical metamaterials is their negative effective dynamic parameters (mass and/or stiffness). Within the framework of mechanical metamaterials, most of the developments up to now have considered linear material behavior only. There is a natural need to understand the effect of nonlinear material behavior on the wave propagation through such engineered composites. In this paper, the dynamic behavior of a discrete lattice system composed of a series of nonlinear local resonators is investigated. By making use of the harmonic balance method, approximating dispersion relations are derived. Unlike previous works, super/sub-harmonic generation has been considered and revealed new phenomenon: the possibility of generating multiple transmission dips. The analysis also showed the tunability and multistability features of the system. The semi-analytical predictions were verified with direct numerical simulations.