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1.
Artigo em Inglês | MEDLINE | ID: mdl-33658321

RESUMO

OBJECTIVE: To determine whether adult cases of Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS) may be related to familial hemophagocytic lymphohistiocytosis (HLH) causes, we have screened patients with adult-onset CLIPPERS for mutations in primary HLH-associated genes. METHODS: In our cohort of 36 patients fulfilling the criteria for probable or definite CLIPPERS according to the CLIPPERS-2017 criteria, we conducted a first study on 12 patients who consented to genetic testing. In these 12 patients, systemic HLH criteria were searched, and genetic analysis of 8 genes involved in primary HLH was performed. RESULTS: Four definite and 8 probable CLIPPERS were enrolled (n = 12). Mutations involved in HLH were identified in 2 definite and 2 probable CLIPPERS (4/12). Three of them had biallelic PRF1 mutations with reduced perforin expression in natural killer cells. The remaining patient had biallelic UNC13D mutations with cytotoxic lymphocyte impaired degranulation. None of the mutated patients reached the criteria for systemic HLH. During follow-up, 3 of them displayed atypical findings for CLIPPERS, including emergence of systemic non-Hodgkin lymphoma (1/3) and confluent gadolinium-enhancing lesions on brain MRI (3/3). CONCLUSIONS: In our patients presenting with adult-onset CLIPPERS, one-third have HLH gene mutations. This genetic treatable condition should be searched in patients with CLIPPERS, especially in those presenting with atypical findings.

3.
Blood ; 136(5): 542-552, 2020 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-32356861

RESUMO

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory condition. Primary HLH occurs early in life as a result of monogenic biallelic mutations affecting lymphocyte cytotoxicity. Secondary HLH occurs mostly in adults secondary to infection, lymphoma, or rheumatic disease. In this latter setting, lymphocyte cytotoxicity status is not known. We conducted a systematic evaluation of natural killer (NK) cell cytotoxicity in adult patients with secondary HLH. Adult patients with secondary HLH were prospectively studied ex vivo for total lymphocyte count and subtype, NK cell phenotype, perforin expression and degranulation, and natural or antibody-dependent cell cytotoxicity, in comparison with patients affected by the same underlying disease without HLH (disease controls [DCs]) and with healthy controls (HCs). Screening for variants of cytotoxity genes was systematically performed. 68 patients were included in the HLH group and 34 each in the DC and HC groups. In HLH patients, severe and transient lymphopenia, activated NK cell phenotype (eg, increased CD69, ICAM-1, HLADR, and CCR5 expression), and decreased capacity of interferon γ production were observed; mean perforin expression was normal; and degranulation tests and NK cell cytotoxicity were not different from those in DCs. A monoallelic variant of uncertain significance affecting a lymphocyte cytotoxicity gene or the perforin variant A91V was observed in almost 50% of the patients. We detected no major intrinsic cytotoxicity dysfunction in secondary HLH patients compared with DCs and no predicted pathogenic gene variant. The activated NK phenotype profile associated with decreased interferon γ production seems similar to those of other hyperinflammatory diseases such as sepsis or systemic juvenile idiopathic arthritis.

5.
Nat Commun ; 11(1): 1817, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32286311

RESUMO

Dendritic cells (DCs) constitute a specialized population of immune cells that present exogenous antigen (Ag) on major histocompatibility complex (MHC) class I molecules to initiate CD8 + T cell responses against pathogens and tumours. Although cross-presentation depends critically on the trafficking of Ag-containing intracellular vesicular compartments, the molecular machinery that regulates vesicular transport is incompletely understood. Here, we demonstrate that mice lacking Kif5b (the heavy chain of kinesin-1) in their DCs exhibit a major impairment in cross-presentation and thus a poor in vivo anti-tumour response. We find that kinesin-1 critically regulates antigen cross-presentation in DCs, by controlling Ag degradation, the endosomal pH, and MHC-I recycling. Mechanistically, kinesin-1 appears to regulate early endosome maturation by allowing the scission of endosomal tubulations. Our results highlight kinesin-1's role as a molecular checkpoint that modulates the balance between antigen degradation and cross-presentation.


Assuntos
Apresentação do Antígeno/imunologia , Células Dendríticas/metabolismo , Endossomos/metabolismo , Cinesina/metabolismo , Ácidos/metabolismo , Animais , Antígenos/metabolismo , Antígenos CD/metabolismo , Células da Medula Óssea/citologia , Proliferação de Células , Endocitose , Antígenos de Histocompatibilidade Classe I/metabolismo , Cinesina/deficiência , Camundongos Knockout , Camundongos Transgênicos , Microtúbulos/metabolismo , Neoplasias/patologia , Ovalbumina/imunologia , Solubilidade
6.
Haematologica ; 105(1): 59-70, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31004027

RESUMO

The molecular machinery that regulates the balance between self-renewal and differentiation properties of hematopoietic stem cells (HSC) has yet to be characterized in detail. Here we found that the tetratricopeptide repeat domain 7 A (Ttc7a) protein, a putative scaffold protein expressed by HSC, acts as an intrinsic regulator of the proliferative response and the self-renewal potential of murine HSC in vivo Loss of Ttc7a consistently enhanced the competitive repopulating ability of HSC and their intrinsic capacity to replenish the hematopoietic system after serial cell transplantations, relative to wildtype cells. Ttc7a-deficient HSC exhibit a different transcriptomic profile for a set of genes controlling the cellular response to stress, which was associated with increased proliferation in response to chemically induced stress in vitro and myeloablative stress in vivo Our results therefore revealed a previously unrecognized role of Ttc7a as a critical regulator of HSC stemness. This role is related, at least in part, to regulation of the endoplasmic reticulum stress response.

7.
Front Immunol ; 10: 2592, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31787977

RESUMO

Mutations in the tetratricopeptide repeat domain 7A (TTC7A) gene cause very early onset inflammatory bowel diseases (VOIBD) or multiple intestinal atresia associated with immune deficiency of various severities, ranging from combined immune deficiency to mild lymphopenia. In this manuscript, we report the clinical, biological and molecular features of a patient born from consanguineous parents, presenting with recurrent lymphoproliferative syndrome and pan-hypergammaglobulinemia associated with chronic intestinal pseudo obstruction (CIPO). Genetic screening revealed the novel c.974G>A (p.R325Q) mutation in homozygosity in the TTC7A gene. The patient's phenotype differs significantly from that previously associated with TTC7A deficiency in humans. It becomes closer to the one reported in the ttc7a-deficient mice that invariably develop a proliferative lymphoid and myeloid disorder. Functional studies showed that the extreme variability in the clinical phenotype couldn't be explained by the cellular phenotype. Indeed, the patient's TTC7A mutation, as well as the murine-ttc7 mutant, have the same functional impact on protein expression, DNA instability and chromatin compaction, as the other mutations that lead to classical TTC7A-associated phenotypes. Co-inheritance of genetic variants may also contribute to the unique nature of the patient's phenotype. The present case report shows that the clinical spectrum of TTC7A deficiency is much broader than previously suspected. Our findings should alert the physicians to consider screening of TTC7A mutations in patients with lymphoproliferative syndrome and hypergammaglobulinemia and/or chronic intestinal pseudo-obstruction.


Assuntos
Pseudo-Obstrução Intestinal/etiologia , Transtornos Linfoproliferativos/etiologia , Deficiência de Proteína , Proteínas/fisiologia , Animais , Células Cultivadas , Doença Crônica , Consanguinidade , Feminino , Humanos , Lactente , Pseudo-Obstrução Intestinal/genética , Transtornos Linfoproliferativos/genética , Masculino , Camundongos , Proteínas/genética
8.
J Clin Immunol ; 39(7): 702-712, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31401750

RESUMO

PURPOSE: Patients with primary immunodeficiency (PID) are at risk of serious complications. However, data on the incidence and causes of emergency hospital admissions are scarce. The primary objective of the present study was to describe emergency hospital admissions among patients with PID, with a view to identifying "at-risk" patient profiles. METHODS: We performed a prospective observational 12-month multicenter study in France via the CEREDIH network of regional PID reference centers from November 2010 to October 2011. All patients with PIDs requiring emergency hospital admission were included. RESULTS: A total of 200 admissions concerned 137 patients (73 adults and 64 children, 53% of whom had antibody deficiencies). Thirty admissions were reported for 16 hematopoietic stem cell transplantation recipients. When considering the 170 admissions of non-transplant patients, 149 (85%) were related to acute infections (respiratory tract infections and gastrointestinal tract infections in 72 (36%) and 34 (17%) of cases, respectively). Seventy-seven percent of the admissions occurred during winter or spring (December to May). The in-hospital mortality rate was 8.8% (12 patients); death was related to a severe infection in 11 cases (8%) and Epstein-Barr virus-induced lymphoma in 1 case. Patients with a central venous catheter (n = 19, 13.9%) were significantly more hospitalized for an infection (94.7%) than for a non-infectious reason (5.3%) (p = 0.04). CONCLUSION: Our data showed that the annual incidence of emergency hospital admission among patients with PID is 3.4%. The leading cause of emergency hospital admission was an acute infection, and having a central venous catheter was associated with a significantly greater risk of admission for an infectious episode.


Assuntos
Serviços Médicos de Emergência , Hospitalização , Doenças da Imunodeficiência Primária/epidemiologia , Adulto , Criança , Controle de Doenças Transmissíveis , Doenças Transmissíveis/etiologia , Gerenciamento Clínico , França/epidemiologia , Humanos , Incidência , Profilaxia Pré-Exposição , Doenças da Imunodeficiência Primária/diagnóstico , Doenças da Imunodeficiência Primária/etiologia , Doenças da Imunodeficiência Primária/terapia , Vigilância em Saúde Pública , Resultado do Tratamento
9.
Proc Natl Acad Sci U S A ; 116(3): 970-975, 2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30591564

RESUMO

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is a critical regulator of cell death and inflammation, but its relevance for human disease pathogenesis remains elusive. Studies of monogenic disorders might provide critical insights into disease mechanisms and therapeutic targeting of RIPK1 for common diseases. Here, we report on eight patients from six unrelated pedigrees with biallelic loss-of-function mutations in RIPK1 presenting with primary immunodeficiency and/or intestinal inflammation. Mutations in RIPK1 were associated with reduced NF-κB activity, defective differentiation of T and B cells, increased inflammasome activity, and impaired response to TNFR1-mediated cell death in intestinal epithelial cells. The characterization of RIPK1-deficient patients highlights the essential role of RIPK1 in controlling human immune and intestinal homeostasis, and might have critical implications for therapies targeting RIPK1.


Assuntos
Diferenciação Celular , Imunidade nas Mucosas/genética , Doenças Inflamatórias Intestinais , Mucosa Intestinal , Proteína Serina-Treonina Quinases de Interação com Receptores , Imunodeficiência Combinada Severa , Linfócitos B/imunologia , Linfócitos B/patologia , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Células Epiteliais/imunologia , Células Epiteliais/patologia , Feminino , Células HCT116 , Células HEK293 , Humanos , Doenças Inflamatórias Intestinais/genética , Doenças Inflamatórias Intestinais/imunologia , Doenças Inflamatórias Intestinais/patologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/patologia , Masculino , Mutação , NF-kappa B/genética , NF-kappa B/imunologia , Proteína Serina-Treonina Quinases de Interação com Receptores/deficiência , Proteína Serina-Treonina Quinases de Interação com Receptores/imunologia , Imunodeficiência Combinada Severa/genética , Imunodeficiência Combinada Severa/imunologia , Imunodeficiência Combinada Severa/patologia , Linfócitos T/imunologia , Linfócitos T/patologia
10.
Nat Genet ; 51(1): 196, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30429576

RESUMO

In the version of this article originally published, the main-text sentence "In three patients of European ancestry, we identified the germline variant encoding p.Ile97Met in TIM-3, which was homozygous in two (P12 and P13) and heterozygous in one (P15) in the germline but with no TIM-3 plasma membrane expression in the tumor" misstated the identifiers of the two homozygous individuals, which should have been P13 and P14. The error has been corrected in the HTML, PDF and print versions of the paper.

12.
Cell Discov ; 4: 61, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30455981

RESUMO

A loss-of-function mutation in tetratricopeptide repeat domain 7A (TTC7A) is a recently identified cause of human intestinal and immune disorders. However, clues to related underlying molecular dysfunctions remain elusive. It is now shown based on the study of TTC7A-deficient and wild-type cells that TTC7A is an essential nuclear protein. It binds to chromatin, preferentially at actively transcribed regions. Its depletion results in broad range of epigenomic changes at proximal and distal transcriptional regulatory elements and in altered control of the transcriptional program. Loss of WT_TTC7A induces general decrease in chromatin compaction, unbalanced cellular distribution of histones, higher nucleosome accessibility to nuclease digestion along with genome instability, and reduced cell viability. Our observations characterize for the first time unreported functions for TTC7A in the nucleus that exert a critical role in chromatin organization and gene regulation to safeguard healthy immune and intestinal status.

13.
Nat Genet ; 50(12): 1650-1657, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30374066

RESUMO

Subcutaneous panniculitis-like T cell lymphoma (SPTCL), a non-Hodgkin lymphoma, can be associated with hemophagocytic lymphohistiocytosis (HLH), a life-threatening immune activation that adversely affects survival1,2. T cell immunoglobulin mucin 3 (TIM-3) is a modulator of immune responses expressed on subgroups of T and innate immune cells. We identify in ~60% of SPTCL cases germline, loss-of-function, missense variants altering highly conserved residues of TIM-3, c.245A>G (p.Tyr82Cys) and c.291A>G (p.Ile97Met), each with specific geographic distribution. The variant encoding p.Tyr82Cys TIM-3 occurs on a potential founder chromosome in patients with East Asian and Polynesian ancestry, while p.Ile97Met TIM-3 occurs in patients with European ancestry. Both variants induce protein misfolding and abrogate TIM-3's plasma membrane expression, leading to persistent immune activation and increased production of inflammatory cytokines, including tumor necrosis factor-α and interleukin-1ß, promoting HLH and SPTCL. Our findings highlight HLH-SPTCL as a new genetic entity and identify mutations causing TIM-3 alterations as a causative genetic defect in SPTCL. While HLH-SPTCL patients with mutant TIM-3 benefit from immunomodulation, therapeutic repression of the TIM-3 checkpoint may have adverse consequences.


Assuntos
Mutação em Linhagem Germinativa , Receptor Celular 2 do Vírus da Hepatite A/genética , Linfo-Histiocitose Hemofagocítica/genética , Linfoma de Células T/genética , Paniculite/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Diagnóstico Diferencial , Feminino , Predisposição Genética para Doença , Humanos , Lactente , Linfo-Histiocitose Hemofagocítica/classificação , Linfo-Histiocitose Hemofagocítica/diagnóstico , Linfoma de Células T/classificação , Linfoma de Células T/diagnóstico , Masculino , Pessoa de Meia-Idade , Paniculite/classificação , Paniculite/diagnóstico , Linhagem , Sequenciamento Completo do Exoma , Adulto Jovem
14.
Cell Mol Gastroenterol Hepatol ; 6(4): 477-493.e1, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30364784

RESUMO

Background & Aims: Microvillus inclusion disease (MVID) is a congenital intestinal malabsorption disorder caused by defective apical vesicular transport. Existing cellular models do not fully recapitulate this heterogeneous pathology. The aim of this study was to characterize 3-dimensional intestinal organoids that continuously generate polarized absorptive cells as an accessible and relevant model to investigate MVID. Methods: Intestinal organoids from Munc18-2/Stxbp2-null mice that are deficient for apical vesicular transport were subjected to enterocyte-specific differentiation protocols. Lentiviral rescue experiments were performed using human MUNC18-2 variants. Apical trafficking and microvillus formation were characterized by confocal and transmission electron microscopy. Spinning disc time-lapse microscopy was used to document the lifecycle of microvillus inclusions. Results: Loss of Munc18-2/Stxbp2 recapitulated the pathologic features observed in patients with MUNC18-2 deficiency. The defects were fully restored by transgenic wild-type human MUNC18-2 protein, but not the patient variant (P477L). Importantly, we discovered that the MVID phenotype was correlated with the degree of enterocyte differentiation: secretory vesicles accumulated already in crypt progenitors, while differentiated enterocytes showed an apical tubulovesicular network and enlarged lysosomes. Upon prolonged enterocyte differentiation, cytoplasmic F-actin-positive foci were observed that further progressed into classic microvillus inclusions. Time-lapse microscopy showed their dynamic formation by intracellular maturation or invagination of the apical or basolateral plasma membrane. Conclusions: We show that prolonged enterocyte-specific differentiation is required to recapitulate the entire spectrum of MVID. Primary organoids can provide a powerful model for this heterogeneous pathology. Formation of microvillus inclusions from multiple membrane sources showed an unexpected dynamic of the enterocyte brush border.


Assuntos
Diferenciação Celular , Enterócitos/patologia , Intestinos/patologia , Síndromes de Malabsorção/metabolismo , Microvilosidades/patologia , Mucolipidoses/metabolismo , Proteínas Munc18/deficiência , Proteínas Munc18/metabolismo , Organoides/metabolismo , Actinas/metabolismo , Animais , Núcleo Celular/metabolismo , Enterócitos/metabolismo , Humanos , Lisossomos/metabolismo , Síndromes de Malabsorção/patologia , Camundongos Knockout , Microvilosidades/metabolismo , Microvilosidades/ultraestrutura , Mucolipidoses/patologia , Organoides/patologia , Organoides/ultraestrutura
15.
Arterioscler Thromb Vasc Biol ; 38(5): 1037-1051, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29519941

RESUMO

OBJECTIVE: Platelet secretion is crucial for many physiological platelet responses. Even though several regulators of the fusion machinery for secretory granule exocytosis have been identified in platelets, the underlying mechanisms are not yet fully characterized. APPROACH AND RESULTS: By studying a mouse model (cKO [conditional knockout]Kif5b) lacking Kif5b (kinesin-1 heavy chain) in its megakaryocytes and platelets, we evidenced unstable hemostasis characterized by an increase of blood loss associated to a marked tendency to rebleed in a tail-clip assay and thrombus instability in an in vivo thrombosis model. This instability was confirmed in vitro in a whole-blood perfusion assay under blood flow conditions. Aggregations induced by thrombin and collagen were also impaired in cKOKif5b platelets. Furthermore, P-selectin exposure, PF4 (platelet factor 4) secretion, and ATP release after thrombin stimulation were impaired in cKOKif5b platelets, highlighting the role of kinesin-1 in α-granule and dense granule secretion. Importantly, exogenous ADP rescued normal thrombin induced-aggregation in cKOKif5b platelets, which indicates that impaired aggregation was because of defective release of ADP and dense granules. Last, we demonstrated that kinesin-1 interacts with the molecular machinery comprising the granule-associated Rab27 (Ras-related protein Rab-27) protein and the Slp4 (synaptotagmin-like protein 4/SYTL4) adaptor protein. CONCLUSIONS: Our results indicate that a kinesin-1-dependent process plays a role for platelet function by acting into the mechanism underlying α-granule and dense granule secretion.


Assuntos
Plaquetas/enzimologia , Hemostasia , Cinesina/metabolismo , Megacariócitos/enzimologia , Ativação Plaquetária , Vesículas Secretórias/enzimologia , Trombose/enzimologia , Trifosfato de Adenosina/sangue , Animais , Plaquetas/ultraestrutura , Modelos Animais de Doenças , Humanos , Cinesina/sangue , Cinesina/deficiência , Cinesina/genética , Megacariócitos/ultraestrutura , Camundongos Endogâmicos C57BL , Camundongos Knockout , Selectina-P/sangue , Agregação Plaquetária , Fator Plaquetário 4/sangue , Via Secretória , Vesículas Secretórias/genética , Vesículas Secretórias/ultraestrutura , Transdução de Sinais , Trombose/sangue , Trombose/genética , Trombose/patologia , Proteínas de Transporte Vesicular/sangue , Proteínas rab27 de Ligação ao GTP/sangue
16.
Clin Immunol ; 188: 52-57, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29330115

RESUMO

Evans syndrome (ES) is defined by the combination of autoimmune hemolytic anemia and immune thrombocytopenia. Clinical presentation includes manifestations of immune dysregulation, found in primary immune deficiencies, autoimmune lymphoproliferative syndrome with FAS (ALPS-FAS), Cytotoxic T Lymphocyte Antigen-4 (CTLA-4) and Lipopolysaccharide-Responsive vesicle trafficking Beige-like and Anchor protein (LRBA) defects. We report the clinical history and genetic results of 18 children with ES after excluding ALPS-FAS. Thirteen had organomegaly, five lymphocytic infiltration of non-lymphoid organs, nine hypogammaglobulinemia and fifteen anomalies in lymphocyte phenotyping. Seven patients had genetic defects: three CTLA4 mutations (c.151C>T; c.109+1092_568-512del; c.110-2A>G) identified by Sanger sequencing and four revealed by Next Generation Sequencing: LRBA (c.2450+1C>T), STAT3 gain-of-function (c.2147C>T; c.2144C>T) and KRAS (c.37G>T). No feature emerged to distinguish patients with or without genetic diagnosis. Our data on pediatric-onset ES should prompt physicians to perform extensive screening for mutations in the growing pool of genes involved in primary immune deficiencies with autoimmunity.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Anemia Hemolítica Autoimune/genética , Antígeno CTLA-4/genética , Mutação , Trombocitopenia/genética , Anemia Hemolítica Autoimune/diagnóstico , Anemia Hemolítica Autoimune/patologia , Criança , Pré-Escolar , Feminino , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Masculino , Púrpura Trombocitopênica Idiopática/genética , Púrpura Trombocitopênica Idiopática/patologia , Trombocitopenia/diagnóstico
17.
Am J Hum Genet ; 101(6): 995-1005, 2017 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-29198722

RESUMO

A recurrent de novo missense variant within the C-terminal Sin3-like domain of ZSWIM6 was previously reported to cause acromelic frontonasal dysostosis (AFND), an autosomal-dominant severe frontonasal and limb malformation syndrome, associated with neurocognitive and motor delay, via a proposed gain-of-function effect. We present detailed phenotypic information on seven unrelated individuals with a recurrent de novo nonsense variant (c.2737C>T [p.Arg913Ter]) in the penultimate exon of ZSWIM6 who have severe-profound intellectual disability and additional central and peripheral nervous system symptoms but an absence of frontonasal or limb malformations. We show that the c.2737C>T variant does not trigger nonsense-mediated decay of the ZSWIM6 mRNA in affected individual-derived cells. This finding supports the existence of a truncated ZSWIM6 protein lacking the Sin3-like domain, which could have a dominant-negative effect. This study builds support for a key role for ZSWIM6 in neuronal development and function, in addition to its putative roles in limb and craniofacial development, and provides a striking example of different variants in the same gene leading to distinct phenotypes.


Assuntos
Proteínas de Ligação a DNA/genética , Deficiência Intelectual/genética , Transtornos Neurocognitivos/genética , Sistema Nervoso Central/anormalidades , Sistema Nervoso Central/embriologia , Códon sem Sentido/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Deformidades Congênitas dos Membros/genética , Disostose Mandibulofacial/genética , Sistema Nervoso Periférico/anormalidades , Sistema Nervoso Periférico/enzimologia
18.
Clin Case Rep ; 5(11): 1743-1749, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29152263

RESUMO

Missense mutations in genes involved in familial hemophagocytic lymphohistiocytosis can delay the onset of this life-threatening disease. In children and adults, early recognition of aspecific features as neurological symptoms is crucial as urgent treatment is required.

19.
Curr Opin Immunol ; 49: 20-26, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28866302

RESUMO

Hemophagocytic lymphohistiocytosis (HLH, also referred to a hemophagocytic syndrome) is a life-threatening condition in which uncontrolled activation of lymphocytes and macrophages, and thus the secretion of large amounts of inflammatory cytokines, leads to a severe hyperinflammatory state. Over the last few decades, researchers have characterized primary forms of HLH caused by genetic defects that impair lymphocytes' cytotoxic machinery. Other genetic causes of HLH not related to impaired cytotoxicity have also recently been identified. Furthermore, the so-called 'acquired' forms of HLH are encountered in the context of severe infections, autoimmune and autoinflammatory diseases, malignancy, and metabolic disorders, and may also be associated with primary immunodeficiencies. This implies that a variety of disease mechanisms can lead to HLH. Today's research seeks to gain a better understanding of the various pathogenetic and environmental factors that converge to induce HLH.


Assuntos
Citotoxicidade Imunológica , Síndromes de Imunodeficiência/imunologia , Inflamação/imunologia , Linfócitos/imunologia , Linfo-Histiocitose Hemofagocítica/imunologia , Animais , Autoimunidade , Suscetibilidade a Doenças , Humanos , Ativação de Macrófagos
20.
Hum Mutat ; 38(10): 1355-1359, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28585352

RESUMO

Griscelli syndrome type 2 (GS2) is a rare and often fatal autosomal recessive, hyperinflammatory disorder. It is associated with hypopigmentation of the skin and the hair, resulting in the characteristic pigment accumulation and clumping in the hair shaft. Loss-of-function mutations in RAB27A, resulting from point mutations, short indel, or large deletions, account for all the cases reported to date. However, several GS2 cases originating from Saudi Arabia lack a genetic diagnosis. Here, we report on a new RAB27A genetic anomaly observed in seven Saudi Arabia families that had remained negative after extensive molecular genomic DNA testing. Linkage analysis and targeted sequencing of the RAB27A genomic region in several of these patients led to the identification of a common homozygous tandem duplication of 38 kb affecting exon 2-5 and resulting in a premature stop codon. The pathogenic effect of this duplication was confirmed by a cDNA analysis and functional assays. The identification of microhomology flanking the breakpoint site suggests a possible underlying mechanism.


Assuntos
Hipopigmentação/diagnóstico , Hipopigmentação/genética , Síndromes de Imunodeficiência/diagnóstico , Síndromes de Imunodeficiência/genética , Linfo-Histiocitose Hemofagocítica/diagnóstico , Linfo-Histiocitose Hemofagocítica/genética , Piebaldismo/diagnóstico , Piebaldismo/genética , Proteínas rab27 de Ligação ao GTP/genética , Códon sem Sentido , Consanguinidade , Éxons/genética , Feminino , Duplicação Gênica/genética , Ligação Genética , Cabelo/patologia , Homozigoto , Humanos , Hipopigmentação/metabolismo , Hipopigmentação/patologia , Síndromes de Imunodeficiência/patologia , Linfo-Histiocitose Hemofagocítica/patologia , Masculino , Mutação/genética , Linhagem , Piebaldismo/patologia , Doenças da Imunodeficiência Primária , Arábia Saudita , Deleção de Sequência , Pigmentação da Pele/genética , Linfócitos T Citotóxicos/patologia
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