Publications by authors named "Ronan Leahy"

Background: Suppressor of cytokine signalling 1 (SOCS1) insufficiency is an inborn error of immunity affecting the negative regulation of cytokine and growth factor signalling. We aimed to enhance the understanding of clinical manifestations, disease trajectories, disease penetrance, and the effect of Janus kinase (JAK) inhibition in individuals with SOCS1 insufficiency.

Methods: This study used data from two independent cohorts: the European Society for Immunodeficiencies (ESID) registry and the UK Biobank.

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Introduction: Chimeric antigen receptor T cells (CAR-Ts) targeting CD19 represent a significant advance in treatment for patients with relapsed/refractory B-cell malignancies. Although a significant minority of recipients are women during their reproductive years, there is a paucity of data regarding pregnancy and neonatal outcomes in women previously treated with CAR-T. This is important as maternal T cells are known to cross the placenta and into breastmilk during pregnancy and breastfeeding, respectively.

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Background: In 2014, germline signal transducer and activator of transcription (STAT) 3 gain-of-function (GOF) mutations were first described to cause a novel multisystem disease of early-onset lymphoproliferation and autoimmunity.

Objective: This pivotal cohort study defines the scope, natural history, treatment, and overall survival of a large global cohort of patients with pathogenic STAT3 GOF variants.

Methods: We identified 191 patients from 33 countries with 72 unique mutations.

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Autoimmunity can occur when a checkpoint of self-tolerance fails. The study of familial autoimmune diseases can reveal pathophysiological mechanisms involved in more common autoimmune diseases. Here, by whole-exome/genome sequencing we identify heterozygous, autosomal-dominant, germline loss-of-function mutations in the SOCS1 gene in ten patients from five unrelated families with early onset autoimmune manifestations.

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History illustrates the remarkable public health impact of mass vaccination, by dramatically improving life expectancy and reducing the burden of infectious diseases and co-morbidities worldwide. It has been perceived that if an individual adhered to the MMR vaccine schedule that immunity to mumps virus (MuV) would be lifelong. Recent mumps outbreaks in individuals who had received two doses of the Measles Mumps Rubella (MMR) vaccine has challenged the efficacy of the MMR vaccine.

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Children with Down syndrome (DS) develop more infections, have an increased mortality from sepsis and an increased incidence of chronic inflammatory conditions. Cytokine dysregulation may underpin these clinical sequelae and raised pro-inflammatory biomarkers are a feature in adults with DS. The importance of the anti-inflammatory mediators IL-1ra and IL-10, as well as cytokines Epo and VEGF, which could impact on the pathogenesis and outcomes in congenital heart disease (CHD) which is more prevalent in DS, are less well known.

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Toll-like receptors (TLRs) are the key in initiating innate immune responses. TLR2 is crucial in recognising lipopeptides from gram-positive bacteria and is implicated in chronic inflammation. Children with Down syndrome (DS) are prone to infections from these pathogens and have an increased risk of autoimmunity.

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Non-canonical NF-κB-pathway signaling is integral in immunoregulation. Heterozygous mutations in have recently been established as a molecular cause of common variable immunodeficiency (CVID) and DAVID-syndrome, a rare condition combining deficiency of anterior pituitary hormone with CVID. Here, we investigate 15 previously unreported patients with primary immunodeficiency (PID) from eleven unrelated families with heterozygous -mutations including eight patients with the common p.

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Article Synopsis
  • Zinc is crucial for human immunity, but its specific molecular roles have not been extensively studied.
  • The research identifies a new genetic disease linked to mutations in the SLC39A7 gene, leading to severe immunodeficiency due to absent B cells and increased infections.
  • The study utilizes CRISPR-Cas9 to model ZIP7 deficiency in mice, revealing that low zinc levels in B cells affect their development and signaling, emphasizing zinc's importance in immune cell function.
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Background: Caspase activation and recruitment domain 11 (CARD11) encodes a scaffold protein in lymphocytes that links antigen receptor engagement with downstream signaling to nuclear factor κB, c-Jun N-terminal kinase, and mechanistic target of rapamycin complex 1. Germline CARD11 mutations cause several distinct primary immune disorders in human subjects, including severe combined immune deficiency (biallelic null mutations), B-cell expansion with nuclear factor κB and T-cell anergy (heterozygous, gain-of-function mutations), and severe atopic disease (loss-of-function, heterozygous, dominant interfering mutations), which has focused attention on CARD11 mutations discovered by using whole-exome sequencing.

Objectives: We sought to determine the molecular actions of an extended allelic series of CARD11 and to characterize the expanding range of clinical phenotypes associated with heterozygous CARD11 loss-of-function alleles.

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Background: In contrast to adult-onset inflammatory bowel disease (IBD), where many genetic loci have been shown to be involved in complex disease etiology, early-onset IBD (eoIBD) and associated syndromes can sometimes present as monogenic conditions. As a result, the clinical phenotype and ideal disease management in these patients often differ from those in adult-onset IBD. However, due to high costs and the complexity of data analysis, high-throughput screening for genetic causes has not yet become a standard part of the diagnostic work-up of eoIBD patients.

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Background: Thymus transplantation is a promising strategy for the treatment of athymic complete DiGeorge syndrome (cDGS).

Methods: Twelve patients with cDGS underwent transplantation with allogeneic cultured thymus.

Objective: We sought to confirm and extend the results previously obtained in a single center.

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Background: Disease severity in viral bronchiolitis is often difficult to predict at onset, and may be related to the host immune response. Recognizing the particular immunologic features of infants who develop severe disease might offer an opportunity for developing diagnostic tools to facilitate early intervention and improve outcomes.

Methods: We compared cytokine gene expression (by real-time reverse-transcriptase polymerase chain reaction), cytokine concentrations (by enzyme-linked immunosorbent assay) and the activation status of lymphocytes (by flow cytometry) in the peripheral blood of children hospitalized with moderate and severe viral bronchiolitis and a group of age-matched controls.

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Despite the advent of antiviral therapy, herpes simplex encephalitis (HSE) remains a devastating condition with significant morbidity and mortality. Neurologic relapse after initial improvement is generally attributed to herpes simplex virus reactivation. In 2013, inflammation caused by anti-N-methyl-D-aspartate receptor antibodies was reported in association with cases of neurologic relapse after herpes simplex encephalitis.

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Disease severity in viral bronchiolitis in infancy is difficult to predict and has been linked to host innate immunity. The study aimed to investigate the innate cytokine interleukin-15 (IL-15) as a marker of disease severity.A prospective single-centre observational study was conducted in a university-affiliated paediatric teaching hospital, comparing children (0-18 months) hospitalised for viral bronchiolitis, those admitted to the paediatric intensive care unit with severe disease and healthy age-matched controls.

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Type I interferon (IFN-α/β) is a fundamental antiviral defense mechanism. Mouse models have been pivotal to understanding the role of IFN-α/β in immunity, although validation of these findings in humans has been limited. We investigated a previously healthy child with fatal encephalitis after inoculation of the live attenuated measles, mumps, and rubella (MMR) vaccine.

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Background: Vaccination against influenza is an important strategy in preventing severe infection among children with acute lymphoblastic leukemia (ALL). Successful vaccination depends on both vaccine and host-related factors. We conducted a study on factors predicting the immunogenicity of the monovalent pandemic H1N1 (pH1N1) influenza A vaccine in children with ALL.

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