Lupus érythémateux systémique et lymphocytes Tg

Le Lupus érythémateux systémique (LES) est une maladie auto-immune systémique caractérisée par une hyperactivité des lymphocytes T et B, à l'origine d'une rupture de tolérance vis à vis des antigènes nucléaires. Sa physiopathologie, complexe, n'eest pas encore bien connue, notamment le rôle des lymphocytes T dans l'hyperactivation des lymphocytes B. Depuis une vingtaine d'années, a été découverte une nouvelle famille de lymphocytes T, les lymphocytes Tgdelta. Ils semblent avoir une place importante dans la réponse immunautaire par un positionnement clé entre l'immunité innée et adaptive. Certaines observations rapportent leur intervention dans les maladies auto-immunes, notamment dans le LES. On distingue, au sein de cette famille de lymphocytes Tgdelta, des sous-types en fonction de leur TCR, les plus connus étant les Vdelta2 et les non Vdelta2. Chez les sujets sains, le taux de Vdelta2 est 2 à 3 fois supérieur à celui des non Vdelta2. En cas d'infection ce taux de Vdelta2 est souvent majoré, à l'exception de certaines infections, comme le CMV, dans lesquelles on retrouve une inversion du ratio Vdelta2 / non Vdelta2 par expansion de la sous-population Vdelta1. Qu'en est-il chez les patients lupiques ? Existe-t-il une modification des sous-populations Vdelta2 et non Vdelta2 dans le sang périphérique ? Si oui, est-elle corrélée à l'activité de la maladie ? Notre étude réalisée chez 48 patients lupiques et 36 sujets sains retrouve une inversion significative du ratio Vdelta2 / non Vdelta2 chez les patients lupiques, liée à une diminution de la sous-population Vdelta2. Nous avons tenu compte chez nos sujets de leur statut sérologique pour le CMV afin d'éviter une confusion possible liée à ce facteur. Aucune corrélation à l'activité de la maladie n'a été retrouvée. Peu d'articles rapportent cette diminution de la population Vdelta2 dans le sang périphérique des patients lupiques. Les mécanismes de cette modification, le rôle de ces lymphocytes dans la physiopathologie du lupus et l'impact des traitements immunosuppresseurs notamment restent à élucider.Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by a high reactivity of Tand B lymphocytes, inducing loss of tolerance against nuclear antigens. Its complex physiopathology is not yet well known, particularly the role of T-cells in B-cells hyperactivation. For twenty years, we have discovered a new family of T-cells : Tgdelta lymphocytes. They seem to take an important part in the immune response by a key positioning between innate and adaptive immunity. Some papers relate their intervention in autoimmune diseases, including in SLE. We distinguish in gdelta T-cells, 2 subsets depending on their TCR, the Vdelta2 and the Vdelta2-cells. In health subjects, the rate of Vdelta2 is 2 to 3 times higher than Vdelta2-. During infection, this Vdelta2 increases, except in some infections, as CMV, in which inversion of Vdelta2 / Vdelta2-ratio results from Vdelta1 expansion. What about patients with SLE ? Are there changes in the Vdelta2 and Vdelta2-subpopulations in the peripheral blood of patients suffering of SLE and is there a correlation with the disease activity ? Our study, including 48 SLE and 36 controls, finds a significant reversal of the Vdelta2 / Vdelta2-ratio in SLE patients due to a decrease of the Vdelta subset. We have taken account in our study of CMV status in order to avoid confusion due to this factor. None correlation with the activity of tthe disease was found. Few items relate this reduction of the Vdelta2 population in peripheral blood of SLE patients. Mechanisms of these changes, role of these gdelta T-cells in SLE pathophysiology and impact of treatment particularly immunosuppressive treatment remain to be elucidated.BORDEAUX2-BU Santé (330632101) / SudocSudocFranceF

Identification of Streptococcus sinensis from a patient with endocarditis using MALDI-TOF mass spectrometry, 16S rDNA- and sodA-based phylogeny

International audienc

Nontuberculous mycobacterial infections in a French hospital: a 12-year retrospective study

Background Nontuberculous mycobacteria (NTM) are environmental organisms associated with a range of infections. Reports of NTM epidemiology are mainly focused on pulmonary infections and isolations, and extrapulmonary infections are less frequently described. Methods We conducted a retrospective study of NTM infections at the Bordeaux University Hospital, France, between January 2002 and December 2013. We used the microbiologic component of the American Thoracic Society/Infectious Diseases Society of America's pulmonary NTM disease criteria to define cases of pulmonary NTM, and patients with isolates from a normally sterile site were classified as having extrapulmonary disease. Results In our setting, 170 patients were included. Pulmonary cases predominated (54.1%), followed by skin and soft tissue infections (22.9%), disseminated cases (10.6%), lymphadenitis (7.7%), bone and joint infections (2.9%) and the remaining 1.8% catheter-related infections. Overall, 16 NTM species were isolated. Mycobacterium avium (31.8%) and M. intracellulare (20%) were the most common species identified, followed by M. marinum (13.5%), M. kansasii (10.6%), M. xenopi (9.4%), rapidly growing mycobacteria (9.4%) and other slowly growing mycobacteria (5.3%). In general, NTM isolates were largely prevalent in people older than 50 (62.4%); patients aged 1-10 year-old exclusively yielded M. avium from lymph nodes, almost cases having being diagnosed after 2007. Among the 121 patients with complete follow-up, 78 (64.5%), 24 (19.8%), and 19 (15.7%) were cured, experienced relapse, or died, respectively. Conclusion In our study, extrapulmonary NTM infections represented almost half of cases, consisting mainly in skin and soft tissue infections. The increase lymphadenitis cases in children after 2007 could be linked to the cessation of mandatory BCG vaccination in France. We observed similar cure rates (64%) between pulmonary and extrapulmonary infections

Characteristics of the 170 subjects included in the study.

<p>Characteristics of the 170 subjects included in the study.</p

Species and site of infection of NTM isolated at the Bordeaux University Hospital, France, between 2002 and 2013 (n = 170).

<p>Species and site of infection of NTM isolated at the Bordeaux University Hospital, France, between 2002 and 2013 (n = 170).</p