Destructive arthritis in a patient with chikungunya virus infection with persistent specific IgM antibodies

<p>Abstract</p> <p>Background</p> <p>Chikungunya fever is an emerging arboviral disease characterized by an algo-eruptive syndrome, inflammatory polyarthralgias, or tenosynovitis that can last for months to years. Up to now, the pathophysiology of the chronic stage is poorly understood.</p> <p>Case presentation</p> <p>We report the first case of CHIKV infection with chronic associated rheumatism in a patient who developed progressive erosive arthritis with expression of inflammatory mediators and persistence of specific IgM antibodies over 24 months following infection.</p> <p>Conclusions</p> <p>Understanding the specific features of chikungunya virus as well as how the virus interacts with its host are essential for the prevention, treatment or cure of chikungunya disease.</p

Molecular Blocking of CD23 Supports Its Role in the Pathogenesis of Arthritis

BACKGROUND: CD23 is a differentiation/activation antigen expressed by a variety of hematopoietic and epithelial cells. It can also be detected in soluble forms in biological fluids. Initially known as the low-affinity receptor for immunoglobulin E (Fc epsilonRII), CD23 displays various other physiologic ligands such as CD21, CD11b/c, CD47-vitronectin, and mannose-containing proteins. CD23 mediates numerous immune responses by enhancing IgE-specific antigen presentation, regulating IgE synthesis, influencing cell differentiation and growth of both B- and T-cells. CD23-crosslinking promotes the secretion of pro-inflammatory mediators from human monocytes/macrophages, eosinophils and epithelial cells. Increased CD23 expression is found in patients during allergic reactions and rheumatoid arthritis while its physiopathologic role in these diseases remains to be clarified. METHODOLOGY/PRINCIPAL FINDINGS: We previously generated heptapeptidic countrestructures of human CD23. Based on in vitro studies on healthy and arthritic patients' cells, we showed that CD23-specific peptide addition to human macrophages greatly diminished the transcription of genes encoding inflammatory cytokines. This was also confirmed by significant reduction of mediator levels in cell supernatants. We also show that CD23 peptide decreased IgE-mediated activation of both human and rat CD23(+) macrophages. In vivo studies in rat model of arthritis showed that CD23-blocking peptide ameliorates clinical scores and prevent bone destruction in a dose dependent manner. Ex-vivo analysis of rat macrophages further confirmed the inhibitory effect of peptides on their activation. Taken together our results support the role of CD23 activation and subsequent inflammatory response in arthritis. CONCLUSION: CD23-blocking peptide (p30A) prevents the activation of monocytes/macrophages without cell toxicity. Thus, targeting CD23 by antagonistic peptide decreases inflammatory markers and may have clinical value in the treatment of human arthritis and allergic reactions involving CD23

Etude experimentale de la dispersion aerienne de particules biotiques en conditions controlees

National audienc

Characterisation of the interaction between a boundary layer and a cavity using Digital Particle Velocimetry with Optical Flow

An Optical Flow technique based on the use of Dynamic Programming has been applied to Particle Image Velocimetry yielding a significant increase in the accuracy and spatial resolution of the velocity field. Results are presented for an interaction between a laminar boundary layer and a cavity. The experimental characterisation of the interaction between a boundary layer and a cavity was developed in order to valid a three dimensional computation code based on the L.E.S. method (Large Eddies Simulation). The main application of this work is the study of the pollutant transport and dispersion in a canyon street. INTRODUCTION The aim of this investigation is to explore the possibility of using an optical flow technique in measuring fluid flow velocity. Classical flow visualisation is based on direct observation of tracer particles. Analysis of subsequent images searching for local displacements allows quantitative measurement of twodimensional flow fields. The optical flow method offer..

Caractéristiques aérodynamiques de la dispersion aérienne des particules biotiques

National audienc

Laboratory study of fungal spore movement using Laser Doppler Velocimetry

International audienc

Preparation of Porosity-Graded SOFC Anode Substrates

Porosity graded anode substrates for solid oxide fuel cells are considered to optimise the gas transport through the substrate by maintaining a high electrochemical activity for fuel oxidation at the anode/solid electrolyte interface. In this work, the fabrication of porosity graded anode substrates, made from nickel oxide and yttria-modified zirconia and produced by dry uni-axial pressing, are described. Using carbon as pore formers and adjusting the particle size distribution in the ceramic NiO-YSZ masses, samples with gradually changing porosity are built up. The sintering behaviour of the individual layers is analysed and partly adjusted so the multi-layer support can be co-fired together with the YSZ electrolyte layer. In the oxidized state, four-layer, porosity graded anode supported half-cells with a dense YSZ electrolyte are demonstrated