Persistent selective T-lymphocytopenia is found both in SCID and congenital athymia. Without molecular diagnosis, it is challenging to determine whether HCT or thymus transplantation ought to be performed. Ex vivo T-lymphopoiesis assays have been proposed to assist clinical decision-making for genetically undefined patients. We investigated 20 T-lymphocytopenic patients, including 13 patients awaiting first-line treatment and 7 patients with failed immune reconstitution after previous HCT or thymus transplantation. Whilst developmental blocks in ex vivo T-lymphopoiesis indicated hematopoietic cell-intrinsic defects, successful T-lymphocyte differentiation required careful interpretation, in conjunction with clinical status, immunophenotyping, and genetic investigations. Of the 20 patients, 13 proceeded to treatment, with successful immune reconstitution observed in 4 of the 6 patients post-HCT and 4 of the 7 patients after thymus transplantation, the latter including two patients who had previously undergone HCT. Whilst further validation and standardization are required, we conclude that assessing ex vivo T-lymphopoiesis during the diagnostic pathway for genetically undefined T-lymphocytopenia improves patient outcomes by facilitating corrective treatment choice.

• Klíčová slova
• Artificial thymic organoids (ATO), Congenital athymia, Diagnostic assays, Ex vivo T-lymphocyte differentiation, Hematopoietic cell transplantation (HCT), Newborn screening, Severe combined immunodeficiency (SCID), T-lymphocytopenia, Thymus transplantation,
• MeSH
• buněčná diferenciace MeSH
• dítě MeSH
• imunofenotypizace MeSH
• kojenec MeSH
• lidé MeSH
• lymfopenie * imunologie   MeSH
• lymfopoéza * genetika   MeSH
• mladiství MeSH
• předškolní dítě MeSH
• primární imunodeficience terapie   genetika   imunologie   MeSH
• T-lymfocyty * imunologie   MeSH
• thymus imunologie   MeSH
• transplantace hematopoetických kmenových buněk * metody   MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Congenital athymia is a life-limiting disorder due to rare inborn errors of immunity causing impaired thymus organogenesis or abnormal thymic stromal cell development and function. Athymic infants have a T-lymphocyte-negative, B-lymphocyte-positive, natural killer cell-positive immunophenotype with profound T-lymphocyte deficiency and are susceptible to severe infections and autoimmunity. Patients variably display syndromic features. Expanding access to newborn screening for severe combined immunodeficiency and T lymphocytopenia and broad genetic testing, including next-generation sequencing technologies, increasingly facilitate their timely identification. The recommended first-line treatment is allogeneic thymus transplantation, which is a specialized procedure available in Europe and the United States. Outcomes for athymic patients are best with early diagnosis and thymus transplantation before the development of infectious and inflammatory complications. These guidelines on behalf of the European Society for Immunodeficiencies provide a comprehensive review for clinicians who manage patients with inborn thymic stromal cell defects; they offer clinical practice recommendations focused on the diagnosis, investigation, risk stratification, and management of congenital athymia with the aim of improving patient outcomes.

• Klíčová slova
• 22q11.2 deletion syndrome, Congenital athymia, DiGeorge syndrome, immunology guidelines, thymus transplantation,
• MeSH
• lidé MeSH
• management nemoci MeSH
• novorozenec MeSH
• syndromy imunologické nedostatečnosti * terapie   diagnóza   imunologie   MeSH
• thymus imunologie   MeSH
• Check Tag
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• směrnice pro lékařskou praxi MeSH
• Geografické názvy
• Evropa MeSH

WW domain binding protein 1-like (WBP1L), also known as outcome predictor of acute leukemia 1 (OPAL1), is a transmembrane adaptor protein, expression of which was shown to correlate with ETV6-RUNX1 translocation and favorable prognosis in childhood leukemia. It has a broad expression pattern in hematopoietic and non-hematopoietic cells. Our previous work described WBP1L as a regulator of CXCR4 signaling and hematopoiesis. Here, we show that hematopoiesis in the mice with Wbp1l germline deletion is dysregulated, already at the level of hematopoietic stem cells and early progenitors. We further demonstrate that thymi of WBP1L-deficient mice are significantly enlarged and contain increased numbers of thymocytes of all subsets. This can potentially be explained by increased generation of multipotent progenitors 4 (MPP4) in the bone marrow, from which the thymus-seeding progenitors are derived. We also observed increases in multiple cell types in the blood. In addition, we show that WBP1L regulates hematopoietic stem cell functionality and leukocyte progenitor proliferation and gene expression during hematopoietic stem and progenitor cell transplantation, which contribute to more efficient engraftment of WBP1L-deficient cells. WBP1L thus emerges as a regulator of hematopoietic stem and progenitor cell function, which controls leukocyte numbers at the steady state and after bone marrow transplantation.

• Klíčová slova
• T cell development, WBP1L, hematopoiesis, hematopoietic stem and progenitor cell transplantation, hematopoietic stem cells, transmembrane adaptor protein,
• MeSH
• hematopoetické kmenové buňky * fyziologie   MeSH
• hematopoéza * MeSH
• membránové proteiny * genetika   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• počet leukocytů MeSH
• regulace genové exprese MeSH
• thymocyty fyziologie   MeSH
• thymus * cytologie   fyziologie   MeSH
• transplantace hematopoetických kmenových buněk MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• membránové proteiny * MeSH
• Wbp1l protein, mouse MeSH Prohlížeč

Thoracic surgery is increasingly influenced by the development of minimally invasive approaches which have also influenced surgery in the area of the anterior mediastinum. The previously standard approach to the thymus via partial sternotomy was gradually replaced by the videothoracoscopic approach in most cases. In recent years, robotically assisted surgery has been gaining ground worldwide in this area, as well. The aim of our paper is to provide a comprehensive overview of procedures in the field of the thymus, including their indications, and to share our first experience with robot-assisted thymus surgery. At the 3rd Department of Surgery, since the start of the robot-assisted thymus surgery program, 23 thymectomies have been performed using this approach, of which 17 were performed for thymoma, 3 for myasthenia gravis, and 3 for parathyroid adenoma localized in thymus tissue. From our experience and the available data, it follows that the length of hospitalization, the rate of complications and the resulting effect of robot-assisted procedures is comparable to VTS procedures; however, the robot-assisted surgery also allows for mini-invasive treatment even in significantly obese patients and in patients with advanced thymic tumors who would otherwise be indicated for open thymectomy.

• Klíčová slova
• myasthenia gravis, robot-assisted surgery, thymectomy, thymoma,
• MeSH
• lidé MeSH
• myasthenia gravis * chirurgie   MeSH
• nádory brzlíku * chirurgie   MeSH
• nádory příštítného tělíska chirurgie   MeSH
• roboticky asistované výkony * metody   MeSH
• thymektomie * metody   MeSH
• thymom * chirurgie   MeSH
• thymus chirurgie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Since its discovery, Aire has been the topic of numerous studies in its role as a transcriptional regulator in the thymus where it promotes the "promiscuous" expression of a large repertoire of tissue-restricted antigens (TRAs) that are normally expressed only in the immune periphery. This process occurs in specialized medullary thymic epithelial cells (mTECs) and mediates the elimination of self-reactive T cells or promotes their conversion to the Foxp3+ regulatory T cell lineage, both of which are required for the prevention of autoimmunity. In recent years, there has been increasing interest in the role of extrathymic Aire expression in peripheral organs. The focus has primarily been on the identification of the cellular source(s) and mechanism(s) by which extrathymic AIRE affects tolerance-related or other physiological processes. A cadre of OMICs tools including single cell RNA sequencing and novel transgenic models to trace Aire expression to perform lineage tracing experiments have shed light on a phenomenon that is more complex than previously thought. In this chapter, we provide a deeper analysis of how extrathymic Aire research has developed and progressed, how cellular sources were identified, and how the function of AIRE was determined. Current data suggests that extrathymic AIRE fulfills a function that differs from what has been observed in the thymus and strongly argues that its main purpose is to regulate transcriptional programs in a cell content-dependent manner. Surprisingly, there is data that also suggests a non-transcriptional role of extrathymic AIRE in the cytoplasm. We have arrived at a potential turning point that will take the field from the classical understanding of AIRE as a transcription factor in control of TRA expression to its role in immunological and non-immunological processes in the periphery.

• Klíčová slova
• AIRE, Fertility, Immune periphery, Non-immune function, RORγt+ eTACs, Sertoli cells, Th17 responses, Transcription function, eTACs, mTECs,
• MeSH
• antigeny MeSH
• autoimunita MeSH
• epitelové buňky metabolismus   MeSH
• regulace genové exprese * MeSH
• thymus MeSH
• transkripční faktory * genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antigeny MeSH
• transkripční faktory * MeSH

Patients with autoimmune polyendocrinopathy syndrome type 1 (APS-1) caused by autosomal recessive AIRE deficiency produce autoantibodies that neutralize type I interferons (IFNs)1,2, conferring a predisposition to life-threatening COVID-19 pneumonia3. Here we report that patients with autosomal recessive NIK or RELB deficiency, or a specific type of autosomal-dominant NF-κB2 deficiency, also have neutralizing autoantibodies against type I IFNs and are at higher risk of getting life-threatening COVID-19 pneumonia. In patients with autosomal-dominant NF-κB2 deficiency, these autoantibodies are found only in individuals who are heterozygous for variants associated with both transcription (p52 activity) loss of function (LOF) due to impaired p100 processing to generate p52, and regulatory (IκBδ activity) gain of function (GOF) due to the accumulation of unprocessed p100, therefore increasing the inhibitory activity of IκBδ (hereafter, p52LOF/IκBδGOF). By contrast, neutralizing autoantibodies against type I IFNs are not found in individuals who are heterozygous for NFKB2 variants causing haploinsufficiency of p100 and p52 (hereafter, p52LOF/IκBδLOF) or gain-of-function of p52 (hereafter, p52GOF/IκBδLOF). In contrast to patients with APS-1, patients with disorders of NIK, RELB or NF-κB2 have very few tissue-specific autoantibodies. However, their thymuses have an abnormal structure, with few AIRE-expressing medullary thymic epithelial cells. Human inborn errors of the alternative NF-κB pathway impair the development of AIRE-expressing medullary thymic epithelial cells, thereby underlying the production of autoantibodies against type I IFNs and predisposition to viral diseases.

• MeSH
• aktivační mutace MeSH
• autoimunitní polyglandulární syndromy MeSH
• autoprotilátky * imunologie   MeSH
• COVID-19 genetika   imunologie   MeSH
• epiteliální buňky štítné žlázy metabolismus   patologie   MeSH
• genetická predispozice k nemoci * MeSH
• heterozygot MeSH
• interferon typ I * antagonisté a inhibitory   imunologie   MeSH
• kinasa indukující NF-kappaB MeSH
• lidé MeSH
• mutace ztráty funkce MeSH
• NF-kappa B - podjednotka p52 nedostatek   genetika   MeSH
• NF-kappa B * nedostatek   genetika   MeSH
• protein AIRE MeSH
• proteiny I-kappa B nedostatek   genetika   MeSH
• thymus abnormality   imunologie   patologie   MeSH
• virová pneumonie genetika   imunologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• autoprotilátky * MeSH
• interferon typ I * MeSH
• NF-kappa B - podjednotka p52 MeSH
• NF-kappa B * MeSH
• proteiny I-kappa B MeSH
• RELB protein, human MeSH Prohlížeč

Development of immunocompetent T cells in the thymus is required for effective defence against all types of pathogens, including viruses, bacteria and fungi. To this end, T cells undergo a very strict educational program in the thymus, during which both non-functional and self-reactive T cell clones are eliminated by means of positive and negative selection1.Thymic epithelial cells (TECs) have an indispensable role in these processes, and previous studies have shown the notable heterogeneity of these cells2-7. Here, using multiomic analysis, we provide further insights into the functional and developmental diversity of TECs in mice, and reveal a detailed atlas of the TEC compartment according to cell transcriptional states and chromatin landscapes. Our analysis highlights unconventional TEC subsets that are similar to functionally well-defined parenchymal populations, including endocrine cells, microfold cells and myocytes. By focusing on the endocrine and microfold TEC populations, we show that endocrine TECs require Insm1 for their development and are crucial to maintaining thymus cellularity in a ghrelin-dependent manner; by contrast, microfold TECs require Spib for their development and are essential for the generation of thymic IgA+ plasma cells. Collectively, our study reveals that medullary TECs have the potential to differentiate into various types of molecularly distinct and functionally defined cells, which not only contribute to the induction of central tolerance, but also regulate the homeostasis of other thymus-resident populations.

• MeSH
• autotolerance * imunologie   fyziologie   MeSH
• buněčná diferenciace MeSH
• chromatin MeSH
• DNA vazebné proteiny metabolismus   MeSH
• endokrinní buňky MeSH
• epitelové buňky cytologie   metabolismus   MeSH
• genetická transkripce MeSH
• ghrelin MeSH
• myši MeSH
• parenchymatická tkáň MeSH
• svalové buňky MeSH
• T-lymfocyty * klasifikace   cytologie   imunologie   MeSH
• thymus * cytologie   imunologie   MeSH
• transkripční faktory MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chromatin MeSH
• DNA vazebné proteiny MeSH
• ghrelin MeSH
• Insm1 protein, mouse MeSH Prohlížeč
• Spib protein, mouse MeSH Prohlížeč
• transkripční faktory MeSH

Mature T cells are selected for recognizing self-antigens with low to intermediate affinity in the thymus. Recently, the relative differences in self-reactivity among individual T-cell clones were appreciated as important factors regulating their fate and immune response, but the role of self-reactivity in T-cell biology is incompletely understood. We addressed the role of self-reactivity in T-cell diversity by generating an atlas of mouse peripheral CD8+ T cells, which revealed two unconventional populations of antigen-inexperienced T cells. In the next step, we examined the steady-state phenotype of monoclonal T cells with various levels of self-reactivity. Highly self-reactive clones preferentially differentiate into antigen-inexperienced memory-like cells, but do not form a population expressing type I interferon-induced genes, showing that these two subsets have unrelated origins. The functional comparison of naïve monoclonal CD8+ T cells specific to the identical model antigen did not show any correlation between the level of self-reactivity and the magnitude of the immune response.

• Klíčová slova
• T cell, T-cell diversity, antigen-inexperienced memory-like CD8 T cells, interferon response, self-reactivity,
• MeSH
• autoantigeny MeSH
• buněčné klony MeSH
• CD8-pozitivní T-lymfocyty * MeSH
• interferon typ I * MeSH
• myši MeSH
• thymus MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• autoantigeny MeSH
• interferon typ I * MeSH

The inevitability of evolution of the adaptive immune system with its mechanism of randomly rearranging segments of the T cell receptor (TCR) gene is the generation of self-reactive clones. For the sake of prevention of autoimmunity, these clones must be eliminated from the pool of circulating T cells. This process occurs largely in the thymic medulla where the strength of affinity between TCR and self-peptide MHC complexes is the factor determining thymocyte fate. Thus, the display of self-antigens in the thymus by thymic antigen presenting cells, which are comprised of medullary thymic epithelial (mTECs) and dendritic cells (DCs), is fundamental for the establishment of T cell central tolerance. Whereas mTECs produce and present antigens in a direct, self-autonomous manner, thymic DCs can acquire these mTEC-derived antigens by cooperative antigen transfer (CAT), and thus present them indirectly. While the basic characteristics for both direct and indirect presentation of self-antigens are currently known, recent reports that describe the heterogeneity of mTEC and DC subsets, their presentation capacity, and the potentially non-redundant roles in T cell selection processes represents another level of complexity which we are attempting to unravel. In this review, we underscore the seminal studies relevant to these topics with an emphasis on new observations pertinent to the mechanism of CAT and its cellular trajectories underpinning the preferential distribution of thymic epithelial cell-derived self-antigens to specific subsets of DC. Identification of molecular determinants which control CAT would significantly advance our understanding of how the cellularly targeted presentation of thymic self-antigens is functionally coupled to the T cell selection process.

• Klíčová slova
• antigen presentation, central tolerance, cooperative antigen transfer, dendritic cells, thymic epithelial cells, thymus,
• MeSH
• autoantigeny * MeSH
• centrální tolerance MeSH
• dendritické buňky * MeSH
• epitelové buňky MeSH
• receptory antigenů T-buněk MeSH
• thymus MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• autoantigeny * MeSH
• receptory antigenů T-buněk MeSH

Medullary thymic epithelial cells (mTECs), which produce and present self-antigens, are essential for the establishment of central tolerance. Since mTEC numbers are limited, their function is complemented by thymic dendritic cells (DCs), which transfer mTEC-produced self-antigens via cooperative antigen transfer (CAT). While CAT is required for effective T cell selection, many aspects remain enigmatic. Given the recently described heterogeneity of mTECs and DCs, it is unclear whether the antigen acquisition from a particular TEC subset is mediated by preferential pairing with a specific subset of DCs. Using several relevant Cre-based mouse models that control for the expression of fluorescent proteins, we have found that, in regards to CAT, each subset of thymic DCs preferentially targets a distinct mTEC subset(s). Importantly, XCR1+-activated DC subset represented the most potent subset in CAT. Interestingly, thymic DCs can also acquire antigens from more than one mTEC, and of these, monocyte-derived dendritic cells (moDCs) were determined to be the most efficient. moDCs also represented the most potent DC subset in the acquisition of antigen from other DCs. These findings suggest a preferential pairing model for the distribution of mTEC-derived antigens among distinct populations of thymic DCs.

• Klíčová slova
• cell biology, central tolerance, cooperative antigen transfer, dendritic cells, immunology, inflammation, mouse, thymic epithelial cells, thymus,
• MeSH
• autoantigeny metabolismus   MeSH
• dendritické buňky imunologie   metabolismus   MeSH
• epitelové buňky imunologie   metabolismus   MeSH
• imunologická tolerance * MeSH
• myši inbrední C57BL MeSH
• myši transgenní MeSH
• myši MeSH
• prezentace antigenu imunologie   MeSH
• thymus cytologie   imunologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• autoantigeny MeSH