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Sainte-Foy-lès-Lyon, France

Braza F.,French Institute of Health and Medical Research | Braza F.,French National Center for Scientific Research | Braza F.,University of Nantes | Chesne J.,French Institute of Health and Medical Research | And 9 more authors.
Allergy: European Journal of Allergy and Clinical Immunology | Year: 2014

B cells are essentially described for their capacity to produce antibodies ensuring anti-infectious immunity or deleterious responses in the case of autoimmunity or allergy. However, abundant data described their ability to restrain inflammation by diverse mechanisms. In allergy, some regulatory B-cell subsets producing IL-10 have been recently described as potent suppressive cells able to restrain inflammatory responses both in vitro and in vivo by regulatory T-cell differentiation or directly inhibiting T-cell-mediated inflammation. A specific deficit in regulatory B cells participates to more severe allergic inflammation. Induction of allergen tolerance through specific immunotherapy induces a specific expansion of these cells supporting their role in establishment of allergen tolerance. However, the regulatory functions carried out by B cells are not exclusively IL-10 dependent. Indeed, other regulatory mechanisms mediated by B cells are (i) the production of TGF-β, (ii) the promotion of T-cell apoptosis by Fas-Fas ligand or granzyme-B pathways, and (iii) their capacity to produce inhibitory IgG4 and sialylated IgG able to mediate anti-inflammatory mechanisms. This points to Bregs as interesting targets for the development of new therapies to induce allergen tolerance. In this review, we highlight advances in the study of regulatory mechanisms mediated by B cells and outline what is known about their phenotype as well as their suppressive role in allergy from studies in both mice and humans. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Calmettes C.,Bordeaux University Hospital Center | Vigouroux S.,Bordeaux University Hospital Center | Labopin M.,University Pierre and Marie Curie | Tabrizi R.,Bordeaux University Hospital Center | And 17 more authors.
Biology of Blood and Marrow Transplantation | Year: 2015

We performed a retrospective study to identify pretransplantation risk factors for steroid-refractory (SR) acute graft-versus host disease (aGVHD) after allogeneic stem cell transplantation from matched donors in 630 adult patients who underwent transplantation at our center between 2000 and 2012. The cumulative incidence (CI) of SR aGVHD was 11.3% ± 2.3%. The identified independent risk factors were matched unrelated donor (hazard ratio [HR], 2.52; P= .001), female donor for male recipient (HR, 1.84; P= .023) and absence of antithymocyte globulin (HR, 2.02; P= .005). Three risk groups were defined according to the presence of these risk factors. In the whole cohort, the CI of SR aGVHD was 3.5% ± 1.7% in the low-risk group (0 risk factor, n= 115), 9.3% ± 1.6% in the intermediate-risk group (1 risk factor, n= 323), and 19.3% ± 2.9% in the high-risk group (2 or 3 risk factors, n= 192). Our study suggests that pretransplantation characteristics might help identify patients at high risk for SR aGVHD. A risk adapted first-line treatment of aGVHD could be evaluated in those patients. © 2015 American Society for Blood and Marrow Transplantation.

Amoura S.,Center Hospitalo University Mustapha Bacha | Dubois V.,Laboratoire HLA | Bouali-Benhalima M.,Center Hospitalo University Mustapha Bacha
Revue Francophone des Laboratoires | Year: 2012

The introduction of solid phase assays for the detection of HLA antibodies in routine led to the application of new algorithms for the immunological monitoring of patients for renal transplantation and has prevented many cases of rejection, which would have been impossible to detect using complement dependent serological techniques In this work, we made a comparative study between two techniques of HLA antibody testing, ELISA and Luminex®. Luminex®'s data were analyzed in two ways, firstly with the cut-off of the supplier and then with the new thresholds established after analysis of discrepancies and identification of antibodies. Following this study, we can argue that both techniques are sensitive. However, the Luminex® technology is more specific and faster. © 2012 - Elsevier Masson SAS - Tous droits réservés.

Touzeau C.,Nantes University Hospital Center | Touzeau C.,French Institute of Health and Medical Research | Gagne K.,Laboratoire HLA | Gagne K.,Laboratoire EA4271 | And 12 more authors.
Human Immunology | Year: 2012

The impact of HLA-DPB1 mismatches after unrelated hematopoietic stem cell transplantation (HSCT) remains controversial. We retrospectively analyzed the impact of permissive/non-permissive HLA-DPB1 mismatches on the outcome of 141 patients who underwent 10/10 HLA allelic-matched unrelated HSCT. Each pair was classified according to the 3 (TCE3) and 4-group (TCE4) algorithm based on DPB1 alleles immunogenicity. Outcome analysis revealed that TCE3 and TCE4 non-permissive HLA-DPB1 disparities were not associated with worsened overall survival, relapse risk neither risk of acute GvHD. Overall, this single center retrospective study does not confirm the adverse prognostic of non-permissive HLA-DPB1 mismatches. © 2012 American Society for Histocompatibility and Immunogenetics.

Fromont P.,Laboratoire HLA | Prie N.,Laboratoire HLA | Simon P.,Laboratoire HLA | Cesbron-Gautier A.,Laboratoire HLA | And 4 more authors.
Transfusion | Year: 2010

BACKGROUND: Granulocyte antibodies have been implicated in allo- and autoimmune neutropenia and in transfusion reactions. STUDY DESIGN AND METHODS: Fifty-one sera from suspected alloimmune neutropenia or transfusion-related acute lung injury (TRALI) and 40 sera from suspected autoimmune neutropenia were tested for granulocyte antibodies using LABScreen MULTI (One Lambda, Inc.), compared with classical tests (flow cytometry [FC] and granulocyte agglutination [GAT] followed by monoclonal antibody-specific immobilization of granulocyte antigens [MAIGA]). RESULTS: In alloimmune situations, 48 sera were concordant (94%), two sera positive for HNA with LABScreen MULTI were negative by FC/GAT and/or MAIGA, and one serum sample negative for HNA with LABScreen MULTI was positive by classical tests. In autoimmune neutropenia, 30 sera were concordant (75%), four sera positive for HNA with LABScreen MULTI were negative by FC/GAT and/or MAIGA, and six sera negative for HNA with LABScreen MULTI were positive by FC/GAT and/or MAIGA. For detection of autoantibodies, the LABScreen MULTI was less concordant. However, with the exception of one case, the discrepancies were observed in sera that did not show a clear specificity. CONCLUSIONS: LABScreen MULTI correlated well with our classical methods for HNA-1 and HNA-2a antibody screening. It can be used for screening blood donors or patients suspected of TRALI, but GAT is still needed for HNA-3a antibody screening. © 2010 American Association of Blood Banks.

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