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Phenotypic and functional characterization of leukocytes in patients with immune system dysregulation
Fejtková, Martina ; Kanderová, Veronika (advisor) ; Vlková, Marcela (referee) ; Balounová, Jana (referee)
Inborn errors of immunity (IEI) are a heterogenic group of diseases of the immune system causing dysregulations of both innate and adaptive immunity. New altered immune-related genes are discovered every year, nowadays reaching over 400. (Tangye et al., 2020) Here three new autoinflammatory disorders of IEI patients are described. Toll-like receptors (TLR) 7 and 8 are endosomal receptors in the innate immune response against external pathogens and endogenous autoantigens. A dysregulation in TLR7 and TLR8 in mice causes autoimmunity and inflammation, however, in humans, the immunopathology of TLR8 and TLR7 remains unclear. We identified a novel X-linked c.1715G>T mutation in TLR8 that leads to autoimmune haemolytic anaemia and autoinflammation in male twins caused by dysregulation in TLR8 and TLR7 response especially in myeloid cells (low TLR8 protein expression, cross-reactivity of TLR8 for TLR7 ligands and enhanced TLR7 response). Hematopoietic cell kinase (HCK) belongs to the Src family of kinases and is involved in myeloid cell migration, adhesion and degranulation. Kinase activity in the immune response must be strictly regulated. In HCK, this regulation is based on C-terminal inhibitory tyrosine, which when phosphorylated, HCK kinase activity is switched off. We identified a heterozygous...
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Cell signaling aberrations in primary immunodeficiencies
Fejtková, Martina ; Kanderová, Veronika (advisor) ; Vlková, Marcela (referee)
Primary immunodeficiencies (PID) are genetic disorders characterized by increased susceptibility to infections and various degrees of immune dysregulation. With the expansion of massive parallel sequencing, an increasing number of defects in immune-related genes is being identified in PID. However, the biological impact of the found mutations is often unknown. It is necessary to devise methods to clarify their causality for disease development, which may also aid therapeutic decisions. One of the novel discoveries are gain-of-function mutations in STAT1 gene, resulting in chronic mucocutaneous candidiasis. Candidiasis may be ameliorated with antimycotics or with targeted JAK-STAT inhibitor, ruxolitinib. For our patient with a novel mutation in STAT1, we developed a simple test for the detection of phospho-STAT molecules in peripheral blood lymphocytes. The test confirmed the gain-of-function character of the identified mutation and was used to monitor ruxolitinib treatment efficacy. In the second patient, who presented with lymphadenopathy and immunodeficiency, the as yet undescribed mutation in CASP8 was found. We proved its loss-of-function property expressed as reduced caspase-8 and caspase-3 cleavage, impaired cellular apoptosis, and decreased NFB-related signaling. The third patient who...
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Immune system dysregulation in type 1 diabetes
Paračková, Zuzana ; Šedivá, Anna (advisor) ; Filipp, Dominik (referee) ; Vlková, Marcela (referee)
Type 1 diabetes (T1D) is an autoimmune disease with multifactorial aetiology that involves an attack of self-reactive cytotoxic CD8 lymphocytes on insulin-producing beta cells in the pancreas. In the T1D pathophysiology, both innate and adaptive immunity mechanisms cooperate in the development of inflammation leading to autoimmune destruction. Autoreactive T lymphocytes are the canonical destructors of the beta cells, and B cells produce autoantibodies; the innate immunity cells are considered the initiators of the pathological autoimmune reaction by promoting T and B cell activation. Here, we provide evidence of both innate and adaptive immunity cell types dysregulation in patients with T1D, and that these changes occur before the onset of the disease. The changes in T regulatory lymphocytes (Tregs) and B cell subpopulations occur already in asymptomatic T1D first-degree relatives. During the first year after the onset of the disease, there is a gradual decrease in the neutrophil numbers in the periphery, which probably infiltrate the pancreas. We have focused more closely on the innate immunity dysregulation and its contribution to T1D pathogenesis. Initially, we describe that neutrophil products called neutrophil extracellular traps (NETs) are able to induce IFNγ-producing T cells through...
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Cell signaling aberrations in primary immunodeficiencies
Fejtková, Martina ; Kanderová, Veronika (advisor) ; Vlková, Marcela (referee)
Primary immunodeficiencies (PID) are genetic disorders characterized by increased susceptibility to infections and various degrees of immune dysregulation. With the expansion of massive parallel sequencing, an increasing number of defects in immune-related genes is being identified in PID. However, the biological impact of the found mutations is often unknown. It is necessary to devise methods to clarify their causality for disease development, which may also aid therapeutic decisions. One of the novel discoveries are gain-of-function mutations in STAT1 gene, resulting in chronic mucocutaneous candidiasis. Candidiasis may be ameliorated with antimycotics or with targeted JAK-STAT inhibitor, ruxolitinib. For our patient with a novel mutation in STAT1, we developed a simple test for the detection of phospho-STAT molecules in peripheral blood lymphocytes. The test confirmed the gain-of-function character of the identified mutation and was used to monitor ruxolitinib treatment efficacy. In the second patient, who presented with lymphadenopathy and immunodeficiency, the as yet undescribed mutation in CASP8 was found. We proved its loss-of-function property expressed as reduced caspase-8 and caspase-3 cleavage, impaired cellular apoptosis, and decreased NFB-related signaling. The third patient who...
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