574 research outputs found
Erratum to: Do RANKL inhibitors (denosumab) affect inflammation and immunity?
Receptor activator of nuclear factor kappa B ligand (RANKL) and its natural antagonist, osteoprotegerin (OPG), are, respectively, an indispensable factor and a potent inhibitor for osteoclast differentiation, activity, and survival. The development of a human monoclonal antibody to RANKL, denosumab, constitutes a novel approach to prevent fragility fractures in osteoporosis, skeletal complications of malignancy, and potentially bone erosions in rheumatoid arthritis (RA). In addition to being expressed by osteoblasts, RANKL is abundantly produced by activated T cells, and synoviocytes in RA, whereas its receptor, RANK, is also expressed by monocytes/macrophages and dendritic cells. However, in preclinical and clinical studies of RA—including patients with some degree of immunosuppression—RANKL inhibitors did not significantly alter inflammatory processes. RANKL, RANK, and OPG deficiency in murine models highlights the important role of this pathway in the development and maturation of the immune system in rodents, including functions of T and/or B cells, whereas OPG overexpression in mice and rats seems innocuous with regard to immunity. In contrast, loss-of-function mutations in humans have more limited effects on immune cells. In clinical studies, the overall rate of infections, cancer, and death was similar with denosumab and placebo. Nevertheless, the risk of severe infections and cancer in some specific tissues remains to be carefully scrutinize
Oscillatory behaviour in Type IA FBG: Ruling out chemical complexity
© 2015 SPIE. Type IA FBG are regenerated gratings that appear in hydrogenated germanosilicate fibre of all types during prolonged UV exposure. The gratings are characterised by a large Bragg wavelength shift and a concomitant increase in the mean fibre core index. Modulated index changes are complex by comparison and significantly weaker, often characterised by oscillatory growth behaviour. Low thermal stability of Type IA gratings suggests a possible chemical role similar to thermally processed optical fibres where autocatalysis has been observed. We show that GeOH and SiOH formation are not out-of-phase and follow each other, with no evidence of autocatalysis, ruling out a chemical origin
Evidence of chemical complexity and laser-driven autocatalysis in type IA FBGs
© OSA 2016. We observe the first chemical complexity for Type IA FBG growth under prolonged UV laser exposure. Out-of-phase oscillatory behaviour in GeOH/SiOH formation provides evidence of laser-driven autocatalysis and chemical origins for grating formation
IL-21 promotes survival and maintains a naive phenotype in human CD4+ T lymphocytes
IL-21 is a key T-cell growth factor (TCGF) involved in innate and adaptive immune response. It contributes to the proliferation of naive, but not memory T lymphocytes. However, the full spectrum of IL-21 activity on T cells remains unclear. Here, we demonstrate that IL-21 primarily maintains the expression of specific naive cell surface markers such as CD45RA, CD27, CD62L and CCR7 on human CD4+ T lymphocytes and that the expression of CCR7 induces cell migration by means of CCL21 chemoattraction. These effects contrast with those of IL-2 which induced the marked proliferation of CD4+ T lymphocytes, leading to an activated-memory phenotype. Nevertheless, IL-21 maintained cell cycle activation and expression of proliferation markers, including proliferating cell nuclear antigen and Ki-67, and triggered T-cell proliferation via TCR and co-stimulation pathways. Unlike IL-2, IL-21 decreased the expression of the anti-apoptotic Bcl-2 protein, which correlated with the absence of activation of the phosphatidylinositol 3′-kinase/Akt signaling pathway. Thus, IL-21 is a TCGF whose function is the preservation of a pool of CD4+ T lymphocytes in a naive phenotype, with a low proliferation rate but with the persistence of cell cycling proteins and cell surface expression of CCR7. These findings strongly suggest that IL-21 plays a part in innate and adaptive immune response owing to homeostasis of T cells and their homing to secondary lymphoid organ
Femtosecond-Laser-Based Inscription Technique for Post-Fiber-Bragg Grating Inscription in an Extrinsic Fabry-Perot Interferometer Pressure Sensor
In this paper, a novel fiber Bragg grating inscription technique based on a femtosecond laser is presented. The grating was inscribed in close proximity to the tip of an extrinsic Fabry-Perot interferometer (EFPI)-based optical fiber pressure sensor. This therefore represents an optical fiber pressure and temperature sensor (OFPTS) for simultaneous pressure and temperature measurement for use in exactly the same physical location. The temperature measurement can also be used to compensate thermal drift in the EFPI sensor
The proinflammatory cytokines IL-2, IL-15 and IL-21 modulate the repertoire of mature human natural killer cell receptors
Natural killer (NK) cells play a crucial role in the immune response to micro-organisms and tumours. Recent evidence suggests that NK cells also regulate the adaptive T-cell response and that it might be possible to exploit this ability to eliminate autoreactive T cells in autoimmune disease and alloreactive T cells in transplantation. Mature NK cells consist of a highly diverse population of cells that expresses different receptors to facilitate recognition of diseased cells and possibly pathogens themselves. Ex vivo culture of NK cells with cytokines such as IL-2 and IL-15 is an approach that permits significant expansion of the NK cell subpopulations, which are likely to have potent antitumour, antiviral, or immunomodulatory effects in autoimmunity. Our data indicate that the addition of IL-21 has a synergistic effect by increasing the numbers of NK cells on a large scale. IL-2 and IL-15 may induce the expression of killer cell immunoglobulin-like receptors (KIRs) in KIR-negative populations, the c-lectin receptor NKG2D and the natural cytotoxic receptor NKp44. The addition of IL-21 to IL-15 or IL-2 can modify the pattern of the KIR receptors and inhibit NKp44 expression by reducing the expression of the adaptor DAP-12. IL-21 also preserved the production of interferon-γ and enhanced the cytotoxic properties of NK cells. Our findings indicate that the proinflammatory cytokines IL-2, IL-15 and IL-21 can modify the peripheral repertoire of NK cells. These properties may be used to endow subpopulations of NK cells with specific phenotypes, which may be used in ex vivo cellular immunotherapy strategies
Embedding low loss polymer optical fibre Bragg gratings:two different approaches
In this paper, we present two different ways to embed polymer fibre Bragg gratings (FBGs) into polymer matrices. In the first experiment, we embedded the FBG into a 3D printed polymer structure, whereas in the second experiment, the coating was polymerized around the fibre. In both cases, the response of the grating was unchanged, without any loss or distortion of the FBG signal compared with the bare fibre response. The design of the polymer coating was optimised for the measurement of a single measurand. We highlighted two possible applications: surface bend deformation monitoring and improved-sensitivity temperature sensing
Donation type and the effect of pre-transplant donor specific antibodies – Data from the Swiss Transplant Cohort Study
Introduction
The type of donation may affect how susceptible a donor kidney is to injury from pre-existing alloimmunity. Many centers are, therefore, reluctant to perform donor specific antibody (DSA) positive transplantations in the setting of donation after circulatory death (DCD). There are, however, no large studies comparing the impact of pre-transplant DSA stratified on donation type in a cohort with a complete virtual cross-match and long-term follow-up of transplant outcome.
Methods
We investigated the effect of pre-transplant DSA on the risk of rejection, graft loss, and the rate of eGFR decline in 1282 donation after brain death (DBD) transplants and compared it to 130 (DCD) and 803 living donor (LD) transplants.
Results
There was a significant worse outcome associated with pre-transplant DSA in all of the studied donation types. DSA directed against Class II HLA antigens as well as a high cumulative mean fluorescent intensity (MFI) of the detected DSA showed the strongest association with worse transplant outcome. We could not detect a significant additive negative effect of DSA in DCD transplantations in our cohort. Conversely, DSA positive DCD transplants appeared to have a slightly better outcome, possibly in part due to the lower mean fluorescent intensity (MFI) of the pre-transplant DSA. Indeed when DCD transplants were compared to DBD transplants with similar MFI (<6.5k), graft survival was not significantly different.
Discussion
Our results suggest that the negative impact of pre-transplant DSA on graft outcome could be similar between all donation types. This suggests that immunological risk assessment could be performed in a similar way regardless of the type of donor kidney transplantation
The impact of pre-transplant donor specific antibodies on the outcome of kidney transplantation - Data from the Swiss transplant cohort study
Background
Pre-transplant donor specific antibodies (DSA), directed at non-self human leukocyte antigen (HLA) protein variants present in the donor organ, have been associated with worse outcomes in kidney transplantation. The impact of the mean fluorescence intensity (MFI) and the target HLA antigen of the detected DSA has, however, not been conclusively studied in a large cohort with a complete virtual cross-match (vXM).
Methods
We investigated the effect of pre-transplant DSA on the risk of antibody-mediated rejection (ABMR), graft loss, and the rate of eGFR decline in 411 DSA positive transplants and 1804 DSA negative controls.
Results
Pre-transplant DSA were associated with a significantly increased risk of ABMR, graft loss, and accelerated eGFR decline. DSA directed at Class I and Class II HLA antigens were strongly associated with increased risk of ABMR, but only DSA directed at Class II associated with graft loss. DSA MFI markedly affected outcome, and Class II DSA were associated with ABMR already at 500-1000 MFI, whereas Class I DSA did not affect outcome at similar low MFI values. Furthermore, isolated DSA against HLA-DP carried comparable risks for ABMR, accelerated eGFR decline, and graft loss as DSA against HLA-DR.
Conclusion
Our results have important implications for the construction and optimization of vXM algorithms used within organ allocation systems. Our data suggest that both the HLA antigen target of the detected DSA as well as the cumulative MFI should be considered and that different MFI cut-offs could be considered for Class I and Class II directed DSA
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