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Le Touquet – Paris-Plage, France

Deau M.-C.,French Institute of Health and Medical Research | Deau M.-C.,University of Paris Descartes | Heurtier L.,French Institute of Health and Medical Research | Heurtier L.,University of Paris Descartes | And 15 more authors.
Journal of Clinical Investigation | Year: 2014

Recently, patient mutations that activate PI3K signaling have been linked to a primary antibody deficiency. Here, we used whole-exome sequencing and characterized the molecular defects in 4 patients from 3 unrelated families diagnosed with hypogammaglobulinemia and recurrent infections. We identified 2 different heterozygous splice site mutations that affect the same splice site in PIK3R1, which encodes the p85α subunit of PI3K. The resulting deletion of exon 10 produced a shortened p85α protein that lacks part of the PI3K p110-binding domain. The hypothetical loss of p85α-mediated inhibition of p110 activity was supported by elevated phosphorylation of the known downstream signaling kinase AKT in patient T cell blasts. Analysis of patient blood revealed that naive T and memory B cell counts were low, and T cell blasts displayed enhanced activation-induced cell death, which was corrected by addition of the PI3Kδ inhibitor IC87114. Furthermore B lymphocytes proliferated weakly in response to activation via the B cell receptor and TLR9, indicating a B cell defect. The phenotype exhibited by patients carrying the PIK3R1 splice site mutation is similar to that of patients carrying gain-offunction mutations in PIK3CD. Our results suggest that PI3K activity is tightly regulated in T and B lymphocytes and that various defects in the PI3K-triggered pathway can cause primary immunodeficiencies. Source


Lemoine R.,French Institute of Health and Medical Research | Lemoine R.,University of Paris Descartes | Pachlopnik-Schmid J.,French Institute of Health and Medical Research | Pachlopnik-Schmid J.,University of Paris Descartes | And 29 more authors.
Journal of Allergy and Clinical Immunology | Year: 2014

Background: Inflammatory bowel disease (IBD) is one of the most common chronic gastrointestinal diseases, but the underlying molecular mechanisms remain largely unknown. Studies of monogenic diseases can provide insight into the pathogenesis of IBD. Objective: We thought to determine the underlying molecular causes of IBD occurring in 2 unrelated families in association with an immune deficiency. Methods: We performed genetic linkage analysis and candidate gene sequencing on 13 patients from a large consanguineous family affected by early-onset IBD, progressive immune deficiency, and, in some cases, autoimmunity and alopecia, a condition we named enteropathy-lymphocytopenia-alopecia. The candidate gene was also sequenced in an unrelated patient with a similar phenotype. We performed histologic analysis of patients' intestinal biopsy specimens and carried out functional assays on PBMCs. Gut organoids derived from a patient's biopsy specimen were analyzed. Results: We identified biallelic missense mutations in tetratricopeptide repeat domain 7A (TTC7A) in all patients from both families. The resulting TTC7A depletion modified the proliferation, adhesion, and migratory capacities of lymphocytes through inappropriate activation of the RhoA signaling pathway. Normal function was restored by wild-type TTC7A expression or addition of a RhoA kinase inhibitor. The growth and polarity of gut epithelial organoids were also found to be dependent on the RhoA signaling pathway. Conclusions: We show that TTC7A regulates the actin cytoskeleton dynamics in lymphocytes through the RhoA signaling pathway and is required in both lymphocytes and epithelial cells for maintaining equilibrium between cell proliferation, migration, polarization, and cell death. Our study highlights variability in the phenotypic expression resulting from TTC7A deficiency and outlines that impairment of both epithelial cells and lymphocytes cooperatively causes IBD. © 2014 American Academy of Allergy, Asthma & Immunology. Source


Lemoine R.,French Institute of Health and Medical Research | Lemoine R.,University of Paris Descartes | Pachlopnik-Schmid J.,French Institute of Health and Medical Research | Pachlopnik-Schmid J.,University of Paris Descartes | And 29 more authors.
Journal of Allergy and Clinical Immunology | Year: 2014

Background Inflammatory bowel disease (IBD) is one of the most common chronic gastrointestinal diseases, but the underlying molecular mechanisms remain largely unknown. Studies of monogenic diseases can provide insight into the pathogenesis of IBD. Objective We thought to determine the underlying molecular causes of IBD occurring in 2 unrelated families in association with an immune deficiency.Results We identified biallelic missense mutations in tetratricopeptide repeat domain 7A (TTC7A) in all patients from both families. The resulting TTC7A depletion modified the proliferation, adhesion, and migratory capacities of lymphocytes through inappropriate activation of the RhoA signaling pathway. Normal function was restored by wild-type TTC7A expression or addition of a RhoA kinase inhibitor. The growth and polarity of gut epithelial organoids were also found to be dependent on the RhoA signaling pathway.MethodsWe performed genetic linkage analysis and candidate gene sequencing on 13 patients from a large consanguineous family affected by early-onset IBD, progressive immune deficiency, and, in some cases, autoimmunity and alopecia, a condition we named enteropathy-lymphocytopenia-alopecia. The candidate gene was also sequenced in an unrelated patient with a similar phenotype. We performed histologic analysis of patients' intestinal biopsy specimens and carried out functional assays on PBMCs. Gut organoids derived from a patient's biopsy specimen were analyzed.Conclusions We show that TTC7A regulates the actin cytoskeleton dynamics in lymphocytes through the RhoA signaling pathway and is required in both lymphocytes and epithelial cells for maintaining equilibrium between cell proliferation, migration, polarization, and cell death. Our study highlights variability in the phenotypic expression resulting from TTC7A deficiency and outlines that impairment of both epithelial cells and lymphocytes cooperatively causes IBD. © 2014 American Academy of Allergy, Asthma & Immunology. Source


Fernandes J.F.,Eurocord | Fernandes J.F.,University of Sao Paulo | Rocha V.,Eurocord | Rocha V.,University of Sao Paulo | And 29 more authors.
Blood | Year: 2012

Pediatric patients with SCID constitute medical emergencies. In the absence of an HLA-identical hematopoietic stem cell (HSC) donor, mismatched related-donor transplantation (MMRDT) or unrelateddonor umbilical cord blood transplantation (UCBT) are valuable treatment options. To help transplantation centers choose the best treatment option, we retrospectively compared outcomes after 175 MMRDTs and 74 UCBTs in patients with SCID or Omenn syndrome. Median follow-up time was 83 months and 58 months for UCBT and MMRDT, respectively. Most UCB recipients received a myeloablative conditioning regimen; most MMRDT recipients did not. UCB recipients presented a higher frequency of complete donor chimerism (P = .04) and faster total lymphocyte count recovery (P = .04) without any statistically significance with the preparative regimen they received. The MMRDT and UCBT groups did not differ in terms of T-cell engraftment, CD4+ and CD3+ cell recoveries, while Ig replacement therapy was discontinued sooner after UCBT (adjusted P = .02). There was a trend toward a greater incidence of grades II-IV acute GVHD (P = .06) and more chronic GVHD (P = .03) after UCBT. The estimated 5-year overall survival rates were 62% ± 4% after MMRDT and 57% ± 6% after UCBT. For children with SCID and no HLA-identical sibling donor, both UCBT and MMRDT represent available HSC sources for transplantation with quite similar outcomes. © 2012 by The American Society of Hematology. Source


Schmid J.P.,French Institute of Health and Medical Research | Schmid J.P.,University of Paris Descartes | Canioni D.,Service dAnatomie et de Cytologie Pathologiques | Moshous D.,French Institute of Health and Medical Research | And 42 more authors.
Blood | Year: 2011

X-linked lymphoproliferative syndromes (XLP) are primary immunodeficiencies characterized by a particular vulnerability toward Epstein-Barr virus infection, frequently resulting in hemophagocytic lymphohistiocytosis (HLH). XLP type 1 (XLP-1) is caused by mutations in the gene SH2D1A (also named SAP), whereas mutations in the gene XIAP underlie XLP type 2 (XLP-2). Here, a comparison of the clinical phenotypes associated with XLP-1 and XLP-2 was performed in cohorts of 33 and 30 patients, respectively. HLH (XLP-1, 55%; XLP-2, 76%) and hypogammaglobulinemia (XLP-1, 67%; XLP-2, 33%) occurred in both groups. Epstein-Barr virus infection in XLP-1 and XLP-2 was the common trigger of HLH (XLP-1, 92%; XLP-2, 83%). Survival rates and mean ages at the first HLH episode did not differ for both groups, but HLH was more severe with lethal outcome in XLP-1 (XLP-1, 61%; XLP-2, 23%). Although only XLP-1 patients developed lymphomas (30%), XLP-2 patients (17%) had chronic hemorrhagic colitis as documented by histopathology. Recurrent splenomegaly often associated with cytopenia and fever was preferentially observed in XLP-2 (XLP-1, 7%; XLP-2, 87%) and probably represents minimal forms of HLH as documented by histopathology. This first phenotypic comparison of XLP subtypes should help to improve the diagnosis and the care of patients with XLP conditions. © 2011 by The American Society of Hematology. Source

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