Publications by authors named "Krisztian Csomos"

WHIM syndrome is typically caused by C-terminal gain-of-function variants in , yet clinical heterogeneity suggests additional genetic modifiers. We investigated a family in which the 22-year-old proband harbored two heterozygous variants: a novel missense variant, c.1022C>A (p.

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B cell-rich tertiary lymphoid structures (TLS) are associated with favorable prognosis and positive response to immunotherapy in cancer. Here we show that simultaneous activation of innate immune effectors, STING and lymphotoxin-β receptor (LTβR), results in CD8 T cell-dependent tumor suppression while inducing high endothelial venule development and germinal center-like B cell responses in tumors to generate functional TLS in a T cell-dependent manner. In a neoadjuvant setting, activation of STING and LTβR by their agonists effectively immunized mice against tumor recurrence, leading to long-term survival.

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Primary immunodeficiencies were initially identified on the basis of recurrent, severe or unusual infections. Subsequently, it was noted that these diseases can also manifest with autoimmunity, autoinflammation, allergy, lymphoproliferation and malignancy, hence a conceptual change and their renaming as inborn errors of immunity. Ongoing advances in flow cytometry provide the opportunity to expand or modify the utility and scope of existing laboratory tests in this field to mirror this conceptual change.

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Article Synopsis
  • Trichothiodystrophy-1 (TTD1) is an autosomal-recessive disease linked to mutations in a gene important for DNA repair and transcription, leading to increased susceptibility to infections in affected patients.
  • The study examined the immune system and DNA repair capabilities of three TTD1 patients, revealing issues such as low antibody responses, problems with B-cell proliferation, and accumulation of DNA damage markers.
  • Findings indicated that TTD1 is associated with antibody deficiencies due to impaired B-cell development and function, confirming the impact of new mutations on the immune system.
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Background: Patients with partial DiGeorge syndrome (pDGS) can present with immune dysregulation, the most common being autoimmune cytopenia (AIC). There is a lack of consensus on the approach to type, combination, and timing of therapies for AIC in pDGS. Recognition of immune dysregulation early in pDGS clinical course may help individualize treatment and prevent adverse outcomes from chronic immune dysregulation.

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Primary immunodeficiencies were initially identified on the basis of recurrent, severe or unusual infections. Subsequently, it was noted that these diseases can also manifest with autoimmunity, autoinflammation, allergy, lymphoproliferation and malignancy, hence a conceptual change and their renaming as inborn errors of immunity. Ongoing advances in flow cytometry provide the opportunity to expand or modify the utility and scope of existing laboratory tests in this field to mirror this conceptual change.

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Mutations in the recombination activating gene 1 () and in humans are associated with a broad spectrum of clinical phenotypes, from severe combined immunodeficiency to immune dysregulation. Partial (hypomorphic) RAG deficiency (pRD) in particular, frequently leads to hyperinflammation and autoimmunity, with several underlying intrinsic and extrinsic mechanisms causing a break in tolerance centrally and peripherally during T and B cell development. However, the relative contributions of these processes to immune dysregulation remain unclear.

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The emergence, survival, growth and maintenance of autoreactive (AR) B-cell clones, the hallmark of humoral autoimmunity, leave their footprints in B-cell receptor repertoires. Collecting IgH sequences related to polyreactive (PR) ones from adaptive immune receptor repertoire (AIRR) datasets make the reconstruction and analysis of PR/AR B-cell lineages possible. We developed a computational approach, named ImmChainTracer, to extract members and to visualize clonal relationships of such B-cell lineages.

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Gain-of-function (GOF) mutations in CXCR4 cause WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome, characterized by infections, leukocyte retention in bone marrow (BM), and blood leukopenias. B lymphopenia is evident at early progenitor stages, yet why do CXCR4 GOF mutations that cause B (and T) lymphopenia remain obscure? Using a CXCR4 R334X GOF mouse model of WHIM syndrome, we showed that lymphopoiesis is reduced because of a dysregulated mesenchymal stem cell (MSC) transcriptome characterized by a switch from an adipogenic to an osteolineage-prone program with limited lymphopoietic activity. We identify lymphotoxin beta receptor (LTβR) as a critical pathway promoting interleukin-7 (IL-7) down-regulation in MSCs.

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Warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome (WS) is a combined immunodeficiency caused by gain-of-function mutations in the C-X-C chemokine receptor type 4 (CXCR4) gene. We characterize a unique international cohort of 66 patients, including 57 (86%) cases previously unreported, with variable clinical phenotypes. Of 17 distinct CXCR4 genetic variants within our cohort, 11 were novel pathogenic variants affecting 15 individuals (23%).

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The recombination-activating genes (RAG) 1 and 2 are indispensable for diversifying the primary B cell receptor repertoire and pruning self-reactive clones via receptor editing in the bone marrow; however, the impact of RAG1/RAG2 on peripheral tolerance is unknown. Partial RAG deficiency (pRD) manifesting with late-onset immune dysregulation represents an 'experiment of nature' to explore this conundrum. By studying B cell development and subset-specific repertoires in pRD, we demonstrate that reduced RAG activity impinges on peripheral tolerance through the generation of a restricted primary B cell repertoire, persistent antigenic stimulation and an inflammatory milieu with elevated B cell-activating factor.

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Article Synopsis
  • APDS is a genetic immune disorder caused by specific mutations, leading to immunodeficiency and issues with B cell regulation, characterized by high transitional B cells, B cell loss, and increased serum IgM levels.!* -
  • A study of 24 APDS patients discovered that their B cells are larger, exhibit higher death rates, impaired class switching, but maintain normal plasmablast differentiation, alongside unusual secretion patterns of antibodies.!* -
  • Findings indicate that the reduced number of B cells is likely due to increased naïve B cell death, while a larger population of specific B cells shows enhanced activation and differentiation, ultimately causing high IgM levels due to impaired class switching.!*
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The T-cell receptor excision circle (TREC) assay detects T-cell lymphopenia (TCL) in newborns and is especially important to identify severe combined immunodeficiency (SCID). A spectrum of SCID variants and non-SCID conditions that present with TCL are being discovered with increasing frequency by newborn screening (NBS). Recombination-activating gene (RAG) deficiency is one the most common causes of classical and atypical SCID and other conditions with immune dysregulation.

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Autoimmunity is becoming an increasingly recognized complication in patients with primary immunodeficiencies (PIDs), including a variety of combined immune deficiencies such as Recombination Activating Gene (RAG) defects. The approach to treating autoimmunity in PID patients is complex, requiring a balance between immunosuppression and susceptibility to infection. Inflammatory arthritis is a feature of immune dysregulation in many PIDs, and the optimal treatment may differ from first line therapies that usually consist of disease-modifying anti rheumatic drugs (DMARDs).

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We report a novel variant in associated with IKAROS haploinsufficiency in a patient with familial immune thrombocytopenia (ITP). IKAROS, encoded by the gene, is a hematopoietic zinc-finger transcription factor that can directly bind to DNA. We show that the identified variant (p.

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Proteins expressed by recombination activating genes 1 and 2 (RAG1/2) are essential in the process of V(D)J recombination that leads to generation of the T and B cell repertoires. Clinical and immunological phenotypes of patients with RAG deficiencies correlate well to the degree of impaired RAG activity and this has been expanding to variants of combined immunodeficiency (CID) or even milder antibody deficiency syndromes. Pathogenic variants that severely impair recombinase activity of RAG1/2 determine a severe combined immunodeficiency (SCID) phenotype, whereas hypomorphic variants result in leaky (partial) SCID and other immunodeficiencies.

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Article Synopsis
  • The text discusses the importance of connecting SCID symptoms to specific genetic causes, especially with advances in newborn screening and gene therapy options.
  • In western countries, X-linked IL2RG and ADA deficiency SCID are prevalent types that can be treated with gene therapy, but diagnosing genetic variants can be challenging due to their polymorphic nature and complexities in coding and non-coding regions.
  • The authors provide examples of X-linked SCID cases where initial tests did not reveal pathogenic variants, highlighting the need for further functional studies and maternal X-inactivation tests to confirm diagnosis and ensure timely eligibility for gene therapy.
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Recent studies identified an emerging role of group 2 and 3 innate lymphoid cells (ILCs) as key players in the generation of T-dependent and T-independent antibody production. In this retrospective case-control study, CD117 ILCs (including the majority of ILC2 and ILC3) were reduced in patients with common variable immunodeficiency (CVID). The reduction in CD117 ILCs was distinctive to CVID and could not be observed in patients with X-linked agammaglobulinemia.

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