Les manifestations auto-immunes chez les patients atteints de déficit immunitaire commun variable et de déficit sélectif en IgA (étude rétrospective de 15 observations recueillies au CHU de Montpellier)

Au cours du déficit immunitaire commun variable (DICV) et du déficit sélectif en IgA (DIgA), il peut y avoir des maladies auto-immunes (MAI). La physiopathologie reste mal expliquée. Nous étudions les MAI chez 15 patients atteints de DICV et DIgA suivis au CHU de Montpellier, et les comparons au groupe de patients ne développant pas de MAI. II s'agit d'une étude rétrospective Monocentrique. Parmi les 26 patients atteints de DICV, 9 ont des MAI, et 6 patients parmi les 12 atteints de DIgA. Les données cliniques et biologiques sont recueillies. Dans le groupe DICV, la MAI la plus fréquente est la thrombocytopénie immune primitive (PTI) (7 patients). 3 patients développent plusieurs MAI. Une seule apparaît dans l'évolution du DICV, chez une patiente substituée en immunoglobulines. La recherche des anticorps (Ac) est souvent positive. Les caractéristiques cliniques et biologiques des patients avec ou sans MAI sont comparables, hormis une fréquence accrue de splénomégalie dans le groupe MAI, et une lymphopénie T (portant sur les CD4 et les CD8). Dans le groupe DIgA, on observe 3 Hashimoto, 2 polyarthrites rhumatoïdes et 1 PTI, apparaissant le plus souvent avant le diagnostic de DlgA. Le faible nombre de patient rend difficile l'interprétation statistique inter-groupes. Les MAI apparaissent souvent avant le diagnostic de déficit immunitaire. L'enjeu parait donc de savoir évoquer un déficit immunitaire devant une MAI. La place d'un phénotypage lymphocytaire est probablement importante au cours de ces pathologies.MONTPELLIER-BU Médecine UPM (341722108) / SudocMONTPELLIER-BU Médecine (341722104) / SudocSudocFranceF

Ergonomic Surgical Practice Analysed Through sEMG Monitoring of Muscular Activity.

International audienc

An Innovative Laparoscopic Instrument Evaluated by SEMG Analysis

International audienceReplacing open surgery in several surgical domains, laparoscopic procedures are responsible for additional solicitations to the surgeons. The shape and length of the instruments lead to non-ergonomic postures. Regions mainly affected are neck, shoulders and distal parts of the upper limbs.EMG activities are used to evaluate the benefit of using a new surgical articulated and motorised hand-held instrument

Study of the Role of LiNi1/3Mn1/3Co1/3O2/Graphite Li-Ion Pouch Cells Confinement, Electrolyte Composition and Separator Coating on Thermal Runaway and Off-Gas Toxicity

A reliable heating device coupled with a FTIR gas analyzer has been tailored with the aim of evaluating the role of state-of-the-art lithium-ion battery components and environmental conditions on thermal and toxic hazards. Here, we demonstrate its effectiveness in accurately assessing the role of fully charged 0.6 Ah pouch cells confinement, electrolyte composition and separator coating on heat release and toxic gas generation-related risks. The fire safety international standards developed by the ISO TC92 SC3 subcommittee were used to determine the asphyxiant and irritant gases toxicity. Cells tighting confinement proves to be a very efficient way to diminish and delay (from 180 to 245 degrees C) the thermal runaway phenomenon occurrence and relating toxic gas release. Vinylene carbonate as electrolyte additive is able to shift (+20 degrees C) the onset temperature, while substitution of 1/3 M LiPF6 by LiFSI does not modify the thermal behavior, nor the toxic risks. The coating of a tri-layer separator influences the irritant gas toxicity related risk, by decreasing fluorinated components release. This study highlights that some improvements regarding LIB safety can be achieved through appropriate component selection and cells integration design at a module/pack level

Graphite electrode thermal behavior and solid electrolyte interphase investigations: Role of state-of-the-art binders, carbonate additives and lithium bis(fluorosulfonyl)imide salt

International audienceThe risk of thermal runaway is, for Li-ion batteries, a critical issue for large-scale applications. This results in manufacturers and researchers placing great emphasis on minimizing the heat generation and thereby mitigating safety-related risks through the search for suitable materials or additives. To this end an in-depth stepwise investigation has been undertaken to provide a better understanding of the exothermic processes that take place at the negative electrode/electrolyte interface as well as an increased visibility of the role of the state-of-the-art electrode binders, additives and lithium salt by means of the classical DSC technique.A reliable experimental set up helped quantify the beneficial or harmful contribution of binder polymers to the exothermic behavior of the CMC/SBR containing graphite electrode film in contact with 1 M LiPF6 in EC:DMC:EMC (1:1:1 v/v/v) electrolyte. Further, the role of the VC, FEC and VEC electrolyte additives (2 wt.%) in reinforcing the protective SEI layer towards thermally induced electrolyte reduction is discussed in the light of infrared spectroscopy and transmission electron microscopy analyzes results.Moreover, after a preliminary corrosion study of LiPF6/LiFSI mixtures, we showed that the 0.66/0.33 molar composition can be used in commercial NMC-based LiBs with a positive effect on the thermal runaway

Safety appraisal of lithium bis(fluorosulfonyl) imide (LiFSI) as electrolyte salt for Li-ion batteries

The success of Li-ion batteries technology relies on a careful evaluation of its safety and subsequently an ad hoc choice of battery key components such as electrolyte salts and solvents, which play a crucial role with respect to safety [1] and proper battery functioning, stabilizing interfacial reactions. The standard electrolyte consists of LiPF6 salt dissolved in carbonates solvents. Thermal instability, moisture sensitivity, and release of HF via hydrolysis of PF6 with protic species suggest a priority for the replacement of LiPF6 with new solutes with improved thermal, chemical and/or electrochemical properties. Thereby, over the past two decades, great efforts have been made hunting for such compounds and lithium imide salts have been found to be of great interest despite some limitations. Within the imide family, there is now a rapidly growing interest for lithium bis(fluorosulfonyl) imide, Li[(FSO2)2N] (LiFSI) to be used in liquid electrolyte owing to well balanced properties such as absence of release of HF under normal operation, low viscosity and high conductivity, high-rate and excellent low temperature performances. In addition storage of LiFSI salt based batteries at both high temperature and fully charged states is no more an issue [2]. The thermal stability comparative study of a fully lithiated graphite powder in presence of carbonates based electrolytes with LiPF6 and LiFSI lithium salt is presented. DSC analysis revealed quite different behaviors. In the LiPF6 case, a broad exotherm starts around 120°C, with the SEI breakdown, ending at 250°C whereas for LiFSI salt, a broad but weak peak starting around 80°C is followed by a sharp exotherm around 200°C. With the help of GC/MS, 19F NMR and ESI-HRMS analyses, the reaction mechanisms involved in these different thermal events were studied and solutions are proposed to noticeably decrease the energy released in the LiFSI case. On the other hand, detailed investigations of the combustion behavior of LiPF6 or LiFSI-based carbonate electrolytes and 1.3 Ah pouch cells were conducted with the objective of getting a better knowledge of lithium-ion battery system fire induced thermal and chemical threats. The well-controlled experimental conditions provided by the Tewarson calorimeter [3] have enabled the accurate evaluation of fire hazard rating parameters such as heat release rate and effective heat of combustion and the quantification of toxic effluents (HF, SO2, NOx…). The comparison of results of these two salts will be discussed.appraisal of lithium bis(fluorosulfonyl) imide (LiFSI) as electrolyte salt for Li-ion batterie

Facile reduction of pseudo-carbonates : promoting solid electrolyte interphases with dicyanoketene alkylene acetals in lithium-ion batteries

In recent years, greener transportation has become of major interest to limit air pollution and global warming. For this purpose, Li-ion batteries (LIBs) are considered as the most promising power source for electric vehicles (EV) and hybrid electric vehicles (HEV) due to their high energy density. The use of high-energy multi-cell battery packs imposes ever more stringent requirements on LIBs in term of safety and long-term cyclability. The formation of an effective SEI passivation layer at the negative electrode / electrolyte interface was found to be of paramount importance in order to enable LIB long-life cycling and controlling the threshold for thermal runaway. This is why SEI-forming additives have been used in the electrolyte to reinforce these protective properties, with the most common additives being vinylene carbonate (VC) (1), fluoroethylene carbonate (FEC) (2), and vinyl ethylene carbonate (VEC) (3). To our knowledge, the modification of EC and PC on the carbonyl group, rather than on the alkylene bridge as for VC, VEC, or FEC, has not previously been attempted.(4,5) It is known that the =C(CN)2 group is an “oxygen equivalent” being even slightly more electronegative than O itself and extending considerably the conjugation. Hence, we hypothesized that modified EC or PC, with C=C(CN)2 replacing the carbonyl groups, could lead to a more facile reduction at higher potentials and a stable SEI. The dicyanoketene propylene (and ethylene) acetal, DCKPA (DCKEA), have both been synthesized according to a simple procedure.(6) The reduction process has been investigated for DCKPA by means of GC/MS and IR analysis and the efficiency as a SEI-reinforcing additive demonstrated by the analysis of the soluble products using liquid GC/MS. The cycling tests using a pouch cell configuration at both 20 and 45°C were realized with only 0.5 wt.% of additive in the electrolyte and resulted in higher capacity retention. Moreover, a post-mortem analysis by DSC revealed an improvement in term of safety due to an improved lithiated graphite/electrolyte interface

T cell Polarization toward T(H)2/T(FH)2 and T(H)17/T(FH)17 in Patients with IgG4-related Disease

International audienceIgG4-related disease (IgG4-RD) is a fibro-inflammatory disorder involving virtually every organ with a risk of organ dysfunction. Despite recent studies regarding B cell and T cell compartments, the disease's pathophysiology remains poorly understood. We examined and characterized subsets of circulating lymphocytes in untreated patients with active IgG4-RD. Twenty-eight consecutive patients with biopsy-proven IgG4-RD were included in a prospective, multicentric study. Lymphocyte's subsets were analyzed by flow cytometry, with analysis of T(H)1/T(H)2/T(H)17, T-FH cells, and cytokine release by peripheral blood mononuclear cells. Results were compared to healthy controls and to patients with primary Sjogren's syndrome. Patients with IgG4-RD showed an increase of circulating T regulatory, T(H)2, T(H)17, and CD4(+)CXCR5(+)PD1(+) TFH cell subsets. Accordingly, increased levels of IL-10 and IL-4 were measured in IgG-RD patients. TFH increase was characterized by the specific expansion of T(FH)2 (CCR6(-)CXCR3(-)), and to a lesser extent of (T(FH)17 (CCR6(+)CXCR3(-))) cells. Interestingly, CD4(+)CXCR5(+)PD1(+) TFH cells normalized under treatment. IgG4-RD is characterized by a shift of circulating T cells toward a T(H)2/T(FH)2 and T(H)17/T(FH)17 polarization. This immunological imbalance might be implicated in the disease's pathophysiology. Treatment regimens targeting such T cells warrant further evaluation

The radiologically isolated syndrome: revised diagnostic criteria

International audienceThe radiologically isolated syndrome (RIS) was defined in 2009 as the presence of asymptomatic, incidentally identified demyelinating-appearing white matter lesions in the central nervous system within individuals lacking symptoms typical of multiple sclerosis. The RIS criteria have been validated and predict the transition to symptomatic MS reliably. The performance of RIS criteria that require fewer MRI lesions is unknown. 2009-RIS subjects, by definition, fulfill 3-4 of 4 criteria for 2005 dissemination in space [DIS] and subjects fulfilling only 1 or 2 lesions in at least one 2017 DIS location were identified within 37 prospective databases. Univariate and multivariate Cox regression models were used to identify predictors of a first clinical event. Performances of different groups were calculated. 747 subjects (72.2% female, mean age 37.7 ± 12.3 years at the index MRI) were included. The mean clinical follow-up time was 46.8 ± 45.4 months. All subjects had focal T2 hyperintensities suggestive of inflammatory demyelination on MRI; 251 (33.6%) fulfilled 1 or 2 2017 DIS criteria (designated as Group 1 and Group 2, respectively), and 496 (66.4%) fulfilled 3 or 4 2005 DIS criteria representing 2009-RIS subjects. Group 1 and 2 subjects were younger than the 2009-RIS Group and were more likely to develop new T2 lesions over time (p < 0.001). Groups 1 and 2 were similar regarding survival distribution and risk factors for transition to multiple sclerosis. At five years, the cumulative probability for a clinical event was 29.0% for Groups 1-2 compared to 38.7% for 2009-RIS (p = 0.0241). The presence of spinal cord lesions on the index scan and CSF-restricted oligoclonal bands in Groups 1-2 increased the risk of symptomatic MS evolution at five years to 38%, comparable to the risk of development in the 2009-RIS group. The presence of new T2 or gadolinium-enhancing lesions on follow-up scans independently increased the risk of presenting with a clinical event (p < 0.001). The 2009-RIS subjects or Group 1-2 with at least 2 of the risk factors for a clinical event demonstrated better sensitivity (86.0%), negative predictive value (73.1%), accuracy (59.8%) and area under the curve (60.7%) compared to other criteria studied. This large prospective cohort brings Class I evidence that subjects with fewer lesions than required in the 2009 RIS criteria evolve directly to a first clinical event at a similar rate when additional risk factors are present. Our results provide a rationale for revisions to existing RIS diagnostic criteria