Publications by authors named "Dessaint J"

Article Synopsis
  • Recent research has advanced our understanding of SARS-CoV-2 and antibody responses, but the detailed composition of circulating antibodies remains largely unexplored.
  • A study using Ig-Seq analyzed the antibody profiles specific to SARS-CoV-2's spike protein and its receptor binding domain in four subjects over six months after infection, revealing that about 50% of RBD-specific IgG did not recognize the spike protein in its stabilized form.
  • The study also evaluated monoclonal antibodies from infected individuals, finding that while some neutralized the virus, others showed limited binding to different variants, highlighting the complexities of the immune response to SARS-CoV-2.
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Data on adverse events from research bronchoscopy with bronchoalveolar lavage (BAL) in patients with cystic fibrosis (CF) is lacking. As research bronchoscopy with BAL is useful for isolation of immune cells and investigation of CF lung microbiome, we sought to investigate the safety of bronchoscopy in adult patients with CF. Between November 2016 and September 2019, we performed research bronchoscopies on CF subjects (32) and control subjects (82).

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Various pathogens use differing strategies to evade host immune response including modulating the host's epigenome. Here, we investigate if EVs secreted from alter DNA methylation in human lung macrophages, thereby potentially contributing to a dysfunctional innate immune response. Using a genome-wide DNA methylation approach, we demonstrate that EVs alter certain host cell DNA methylation patterns.

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, a Gram-negative bacterium, is one of the most common pathogens colonizing the lungs of cystic fibrosis patients. secrete extracellular vesicles (EVs) that contain LPS and other virulence factors that modulate the host's innate immune response, leading to an increased local proinflammatory response and reduced pathogen clearance, resulting in chronic infection and ultimately poor patient outcomes. Lung macrophages are the first line of defense in the airway innate immune response to pathogens.

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Cystic fibrosis (CF) is a genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, resulting in chronic bacterial lung infections and tissue damage. CF macrophages exhibit reduced bacterial killing and increased inflammatory signaling. Iron is elevated in the CF lung and is a critical nutrient for bacteria, including the common CF pathogen Pseudomonas aeruginosa (Pa).

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Article Synopsis
  • Several pulmonary diseases, like cystic fibrosis and smoking-related COPD, show a pattern of being more prevalent in the upper lobes of the lungs, which differ physiologically and metabolically from the lower lobes.
  • The study investigated whether regional differences in the lung could lead to DNA methylation changes in lung macrophages, which may affect their response to environmental challenges.
  • Using advanced DNA methylation techniques, the researchers found 95 specific CpG loci with significant methylation differences, linking these changes to inflammatory processes and metabolic variations in lung macrophages.
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Cigarette smoke inhalation exposes the respiratory system to thousands of potentially toxic substances and causes chronic obstructive pulmonary disease (COPD). COPD is characterized by cycles of inflammation and infection with a dysregulated immune response contributing to disease progression. While smoking cessation can slow the damage in COPD, lung immunity remains impaired.

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Previous work from our group indicated an association between the gastrointestinal microbiota of infants with cystic fibrosis (CF) and airway disease in this population. Here we report that stool microbiota of infants with CF demonstrates an altered but largely unchanging within-individual bacterial diversity (alpha diversity) over the first year of life, in contrast to the infants without CF (control cohort), which showed the expected increase in alpha diversity over the first year. The beta diversity, or between-sample diversity, of these two cohorts was significantly different over the first year of life and was statistically significantly associated with airway exacerbations, confirming our earlier findings.

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Article Synopsis
  • Lung macrophages play a crucial role in the immune response in the lungs, but in cystic fibrosis (CF), they show dysfunctional behavior, leading to excessive inflammation.
  • This study examines DNA methylation changes in lung macrophages from CF patients compared to healthy individuals using advanced techniques like the MethylationEPIC array and next-generation sequencing.
  • Findings reveal significant differences in DNA methylation patterns, with many CpG sites being hypo-methylated in CF, suggesting these epigenetic alterations contribute to the dysfunction of immune cells in the CF lung.
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There are currently no standardized protocols for pre-analytical handling of urine to best preserve small RNA for miRNA profiling studies. miRNA is an attractive candidate as a potential biomarker because of the high level of stability in body fluids and its ability to be quantified on multiple high-throughput platforms. We present a comparison of small RNA recovery and stability in urine under alternate pre-analytical handling conditions and extend recommendations on what conditions optimize yield of miRNA from cell-free urine and urine extracellular vesicles (EVs).

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Slow reconstitution of T cell immunity remains a critical issue after umbilical cord blood (CB) transplantation. Although this may be a consequence of the low cell dose, it may also reflect the propensity of naïve T cells, which predominate in CB, to undergo apoptotic cell death. Exogenous interleukin 7 (IL-7) can prevent apoptosis of naïve T cells, but at high concentrations, IL-7 may also expand alloreactive T cells, thereby aggravating the risk of graft-versus-host disease.

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In longitudinal clinical studies, receiving a high percentage of allogeneic donor-derived CD4(+) CCR7(+) T cells, which include naïve and central memory subsets have been correlated with increased incidence and severity of acute GVHD. Whether naïve and central memory CD4(+) T-cell subsets contribute more or equally to alloimmune responses are still unclear in human. The aim of this study was to investigate in vitro the alloreactive response of purified naïve, central memory, and effector memory CD4(+) T-cell subsets in HLA identical setting.

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Background: Malignant pleural effusions (MPE) are a common and fatal complication in cancers including lung or breast cancers, or malignant pleural mesothelioma (MPM). MPE animal models and immunotherapy trials in MPM patients previously suggested defects of the cellular immunity in MPE. However only few observational studies of the immune response were done in MPM patients, using questionable control groups (transudate…).

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To assess the impact of homeostatic expansion on the occurrence of acute GVHD after reduced intensity conditioning (RIC) transplantation, systemic levels of IL-7 and IL-15 and expression of their specific receptor chains were prospectively investigated in 45 fully HLA-matched allograft recipients. IL-7 and IL-15 levels peaked at four- to fivefold over pre-conditioning values. IL-7 levels were inversely correlated to absolute T-cell counts.

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T-cell reconstitution after allo-SCT initially depends on homeostatic peripheral expansion of donor T cells, the level of which may promote the differentiation of alloreactive and tumor-reactive effectors. IL-7 and IL-15 exert their effect as key homeostatic cytokines. We prospectively investigated plasma levels of IL-7 and IL-15 in a homogeneous group of 40 patients in CR of their hematologic malignancy undergoing myeloablative, fully (10/10) HLA-matched BMT.

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Allogeneic stem cell transplantation has become standard therapy for hematologic malignancies through the positive immunologic graft-versus-leukemia effect. Initial immune recovery relies on peripheral expansion of infused T cells, which switch to a memory-like phenotype. This study prospectively investigated whether changes in subset composition precedes complications after myeloablative HLA-matched transplantation for hematologic malignancies.

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Purpose: The treatment of primary central nervous system lymphoma (PCNSL) and its subset, primary intraocular lymphoma (PIOL), remains of limited efficiency, and salvage therapies are often used without prior testing in adequate animal models. Most PNCSL/PIOL are aggressive B-cell malignancies. Two animal models that closely mimic the human situation were established to evaluate the efficiency of intravitreal and intracerebral anti-CD20 monoclonal antibody (rituximab) injections.

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Background: Pulmonary fibrosis in systemic sclerosis (SSc) involves inflammatory processes in the lower respiratory tract. Analysis of exhaled breath condensate (EBC) is a non-invasive method for studying inflammatory mediators, such as cytokines, which are of interest from both physiological and therapeutic perspectives. The aim of this study was to assess and compare cytokine concentrations in the EBC of SSc patients and controls.

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Objectives: Waldenstrom Macroglobulinemia (WM) is a B-cell neoplasm characterised by secretion of IgM by lymphoplasmacytic bone marrow cells and by cytopenias and hypogammaglobulinemia in a subset of patients. Beta-2 microglobulin (b2m) is a major prognostic factor in WM and the heavy chain of HLA class I molecules, which are known to have immunosuppressive properties and have been implicated in the pathogeny of several malignancies.

Methods: We assessed the serum levels of the total soluble HLA-I molecules and the HLA-Gs molecules in 105 patients with IgM-related disorders [WM (n = 42) and IgM MGUS (n = 63)], and compared the results to 41 healthy subjects.

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Objective: Donor T cells expressing lymph node homing receptors are the foremost initiators of acute graft-vs-host disease (aGVHD), and a high proportion of CD4(+)CCR7(+) T cells in human leukocyte antigen-matched allografts has been shown to confer a high risk of aGVHD without interfering in other outcomes.

Methods: Naïve, central memory (T(CM)), effector memory (T(EM)), and terminally differentiated effector memory (T(TD)) subsets, further subdivided by CD28 expression, were compared in 52 bone marrow and 37 granulocyte colony-stimulating factor-mobilized peripheral blood harvests.

Results: CCR7(+) cells (naïve and T(CM)) predominated in the CD4(+) population, whereas CD8(+) memory cells were chiefly CCR7(neg) in the grafts.

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We sequentially analyzed the serum IgG response against normal mouse brain during experimental autoimmune encephalomyelitis in SJL/J mice injected with CFA, Bordetella pertussis toxin (BPT) and proteolipid protein 139-151 peptide, compared with mice that received CFA and BPT or were uninjected. Dynamic changes were observed from day 0 to day 28 in the 3 groups. Six highly discriminant antigenic bands (kappa=0.

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CC-chemokine receptor 7 (CCR7), a chemokine receptor required for transmigration into lymphoid organs, is only expressed by naive and central memory T cells. T cells with a capacity of homing into lymphoid organs can initiate acute graft-versus-host disease (GVHD) in mice and respond vigorously in vitro to alloantigens in humans, but their impact on clinical outcomes is unknown. We evaluated prospectively the distribution of naive, central memory and CCR7neg memory T-cell subsets in 39 bone marrow and 23 granulocyte colony-stimulating factor-mobilized peripheral blood stem cell allografts and investigated their impact on patient outcomes.

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Memory T cells can be classified as central memory (T(CM), CD45RA(neg)CCR7(+)), effector memory (T(EM), CD45RA(neg)CCR7(neg)), and terminally differentiated cells (T(TD), CD45RA(+)CCR7(neg)) with different homing and effector capacities. In 101 healthy subjects aged from 5 to 96 years, distinct dynamics were evidenced between circulating CD4(+) and CD8(+) T cell populations. Naive CD4(+) and CD8(+) T cells decreased linearly with age, CD8(+) twice more rapidly.

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