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  • Medizin  (8)
  • XA 33000  (8)
  • 1
    In: Blood, American Society of Hematology, Vol. 128, No. 22 ( 2016-12-02), p. 1508-1508
    Kurzfassung: Iron deficiency in young adult males is rare and necessitates prompt investigations. Here we describe a previously healthy 22-year-old male suffering from gastrointestinal bleeding leading to iron deficiency anemia and explained by a constitutional disease. His diagnosis was obtained after detecting a homozygous CTC1 mutation in his germline DNA. Conserved telomere maintenance component 1 (CTC1) is a part of the conserved telomere-associated complex (CST) participating in telomere replication. CST seems to have a role in resolving replication stress also in non-telomeric regions, but little is known about the exact mechanisms. Biallelic, typically compound heterozygous mutations in CTC1 are known to cause cerebroretinal microangiopathy with calcifications and cysts(CRMCC), which is considered as a telomere disease. It is a highly pleiotropic multi-organ disease characterized by abnormalities e.g. in the brain, retina, intestinal vasculature, as well as bone marrow failure (BMF). Some CRMCC patients have dyskeratosis congenita (DC) -like skin, nail, mucosal, and hair changes. Most patients are diagnosed in early childhood and die before teens. To date 37 patients with CRMCC and CTC1 mutations have been reported. The patient was referred to hematology due to iron deficiency anemia with coinciding thrombocytopenia. He also had a notable lymphopenia but no tendency for viral infections or other signs of immunodeficiency. Imaging revealed a patent umbilical vein, widened portal vein, and hepatosplenomegaly without parenchymal changes or lymphadenopathy. Gaucher's disease was excluded by glucocerebrosidase and genetic tests. Histology of a liver biopsy was normal. Based on these findings an idiopathic portal hypertension was diagnosed. Endoscopy revealed gastric antral vascular ectasia. The bone marrow was hypoplastic and pancytopenia persisted after supplementation with iron. He had no known family history of BMF. The patient's telomere length analyzed by a semi-quantitative PCR-test was within the normal range compared to healthy controls of the same age group. We then sequenced the patient's germline exome. Roche MedExome kit was used to target the coding regions of the genome and sequencing conducted using an Illumina HiSeq1500 sequencer. The quality of the data was assessed and the sequence data analyzed using an in-house developed analysis pipeline. The mutation analysis was targeted to genes previously reported to cause immune deficiencies, myelodysplastic syndrome and BMF. The average sequence coverage was 59x, translating into 95% of the exome being covered with a minimum of 20x. Common polymorphisms were excluded from the analysis. The patient was identified to carry a homozygous variation in CTC1 exon 12; c.1994T 〉 G, p.V665G (rs199473676). The variant has previously been reported pathogenic, but all previously reported cases of p.V665G are compound heterozygous (in the majority of cases V665G and a frameshift mutation). The minor allele frequency for this variant in Finns is 0.0015 (10/6612 alleles) and 0.0001 (13/120608) in total (ExAC database) suggesting this mutation is a Finnish founder mutation. We validated the finding by capillary sequencing. The variant was detected heterozygous in both parents ruling out a larger deletion and verifying the mode of inheritance. A healthy sister did not carry the mutation. Identification of CTC1 p.V665G homozygosity raised a high suspicion of CRMCC and further investigations were indicated. Retinal examination as well as brain MRI/MRA revealed multiple lesions characteristic for CRMCC. This is the first report on homozygous CTC1 p.V665G and the second describing CTC1-homozygosity associated with CRMCC, strengthening the disease-causality of biallelic missense mutations in CTC1. The identification of a homozygous CTC1 p.V665G may also open new prospects for studying the effects of the mutation. Our case shows the importance and capacity of new genomic techniques in clinical management, as well: The patient's primary phenotype with iron deficiency anemia, thrombopenia and hepatosplenomegaly could have been explained by only an idiopathic portal hypertension. However, with exome sequencing we were able to reveal a more complex disease entity with major impact on patient's future care and genetic counseling, highlighting the value of germline sequencing in modern diagnostics. Disclosures No relevant conflicts of interest to declare.
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 2016
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    In: Blood, American Society of Hematology, Vol. 125, No. 4 ( 2015-01-22), p. 639-648
    Kurzfassung: Germline activating STAT3 mutations were detected in 3 patients with autoimmunity, hypogammaglobulinemia, and mycobacterial disease. T-cell lymphoproliferation, deficiency of regulatory and helper 17 T cells, natural killer cells, dendritic cells, and eosinophils were common.
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 2015
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    In: Blood, American Society of Hematology, Vol. 126, No. 23 ( 2015-12-03), p. 206-206
    Kurzfassung: The NFkB signaling pathway is a master regulator of the immune response. Recently, dominant mutations in NFKB2 have shown to cause antibody deficiency with adrenal insufficiency. We investigated two families with antibody deficiency and autoinflammatory features, with onset in teenage years and early adulthood (Fig. 1 and Table 1). In family 1, all patients available to study presented with respiratory tract infections and B cell dysfunction marked by hypogammaglobulinemia, poor antibody response to vaccines, or low switched memory B cell counts. Several experienced recurrent episodes of aphthous mucositis in upper gastrointestinal and genital area, sometimes accompanied by abdominal pain, monoarthritis, or fever with elevated inflammatory markers (peripheral blood leukocytes 〉 10x106 cells/ml, C reactive protein 〉 100 mg/L). A lesional biopsy revealed lymphocytic small cell vasculitis reminiscent of Behcet's disease. In family 2, all patients presented with respiratory tract infections, hypogammaglobulinemia, and poor vaccine responses. Based on the pedigrees, we assumed autosomal dominant inheritance. For family 1, we performed genotyping and linkage analysis coupled with whole genome sequencing to pinpoint the causative variant. Linkage analysis showed a 15.4 Mb haplotype on chr4 segregating with the phenotype in all affected individuals. When focusing our search on novel, heterozygous variants negatively affecting conserved residues, we identified only one variant in this genomic location, localizing to NFKB1 gene (p.H67R). In family 2, we exome sequenced one affected individual and filtered the data for novel heterozygous variants negatively affecting conserved residues. This resulted in 17 variants, out of which the I553M NFKB1 variant was considered the best candidate. Several functional analyses showed that the mutations had a negative impact on NFKB1 function. The H67R variant increased NFKB1 affinity to NEMO and delayed protein entry to nucleus, when assessed by affinity purification mass spectrometry and immunofluorescence microscopy. The mutation also decreased NFKB1 transcriptional activity, when expressed together with an NFkB-responsive luciferase reporter, and showed a neomorphic DNA binding pattern on chromatin immunoprecipitation-sequencing. Furthermore, the cell growth was hampered when the mutant NFKB1 was overexpressed in cultured HEK293 cells. The I553M showed a similar negative effect on cultured cell proliferation. Furthermore, the I553M variant negatively affected serine S907 and S893 phosphorylation, leading to defective posttranslational processing of the full-length NFKB1 upon TNF stimulation. To conclude, we show that hypogammaglobulinemia and Behcet's disease-like autoinflammatory syndrome can be caused by mutations in NFKB1. This suggests that a subset of Behcet's disease cases may be of monogenic origin, and highlights the role of NFkB complex in B cell maturation and innate immune regulation. Table 1. Patient characteristics Patient 1 2 3 4 5 6 7 8 9 10 11 12 Age 55 43# 25 29 40 30 37 7 10 60# 61 32 Sex F M F F F F M F M M F M Mutation status H67R ND H67R H67R H67R H67R H67R H67R H67R ND I553M I553M Immunodeficiency Infections URTI RTI URTI - URTI URTI URTI URTI - RTI RTI RTI Antibody deficiency Hypogammaglobulinemia, SAD ND Hypogammaglobulinemia, SAD - IgG subclass deficiency, SAD Hypogammaglobulinemia, SAD Hypogammaglobulinemia, SAD Hypogammaglobulinemia Hypogammaglobulinemia Hypogammaglobulinemia Hypogammaglobulinemia, SAD SAD Immunoglobulin replacement + - + - - + + - - - + - Immune dysregulation Febrile attacks - + + + - - + + - - - - Complex aphtae Mouth, genitalia ND Mouth, genitalia Mouth, genitalia - Mouth Esophagus Mouth, esophagus - - - - Arthritis Monoarthritis - Monoarthritis Monoarthritis - - - - - - Oligoarthritis - Gut disease Periodic abdominal pain, chronic idiopathic diarrhea ND Periodic abdominal pain, microscopic colitis Periodic abdominal pain - - - Periodic abdominal pain - ND Chronic idiopathic diarrhea Coeliac disease Other - Hyperinflammatory response and death after gallbladder surgery - Iritis, Hyperinflammatory response to tooth excision Kidney tumor - Rudimentary left kidney - - - Astma, hypothyreosis - URTI, upper respiratory tract infections; RTI, respiratory tract infections including recurrent pneumonia; SAD, Specific antibody deficiency; ND, No data; #Death age Figure 1. Family pedigrees. Figure 1. Family pedigrees. Disclosures Mustjoki: Sigrid Juselius Foundation: Research Funding; Signe and Ane Gyllenberg Foundation: Research Funding; the Finnish Cancer Societies: Research Funding; Novartis: Honoraria, Research Funding; Academy of Finland: Research Funding; Finnish Cancer Institute: Research Funding; Pfizer: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding. Saarela:Roche: Honoraria.
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 2015
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    In: Blood, American Society of Hematology, Vol. 118, No. 21 ( 2011-11-18), p. 936-936
    Kurzfassung: Abstract 936 BACKGROUND: T-cell large granular lymphocyte (LGL) leukemia is an uncommon lymphoproliferative disorder characterized in most cases by expansion of mature, clonal CD3+CD8+ cytotoxic T lymphocytes (CTLs). The pathogenesis of LGL-leukemia is unknown, and leukemic cells closely resemble normal terminally differentiated effector memory CTLs. While resistance to apoptotic pathways (Fas/Fas ligand, sphingolipid) and activation of survival signaling pathways (Ras) have been implicated in LGL leukemia, the underlying genetic defects have not yet been elucidated. We aimed to identify somatic mutations in LGL leukemia by whole exome sequencing of leukemic and matched healthy control cells. METHODS: Our index patient is a 70 year-old male with untreated CD8+ LGL leukemia diagnosed in 2009 with a clonal rearrangement in the T-cell receptor (TCR) delta and gamma gene. He has been asymptomatic with grade 2 neutropenia and an absolute lymphocyte count of 4–15 ×109/L. The patient had one large predominant T-cell clone: 94% of CD8+ cells consisted of a single Vβ16 clone, as assessed by flow cytometry. No clonal expansions were observed in the CD4+ fraction. DNA was extracted from FACS-sorted CD8+ (leukemic) and CD4+ (control) cells and sequenced by exome capture using an Agilent SureSelect All exon 50 MB capture kit and the Illumina GAII sequencing platform. Candidate somatic mutations were identified with a bioinformatics pipeline consisting of BWA for sequence alignment, Samtools for alignment filtering and Varscan for somatic mutation calling. Mutations were manually reviewed in IGV for alignment artifacts and validated by capillary sequencing. DNA samples from 8 additional untreated LGL-leukemia patients were used for further screening of confirmed somatic mutations by capillary sequencing. From six of these patients DNA was extracted from CD8 sorted cells and from two patients from whole blood. RESULTS: Whole exome sequencing of CD8+ leukemic DNA from the index patient identified a missense mutation in the STAT3 gene (D661V), which was subsequently confirmed by capillary sequencing. As STAT3 signaling has been associated with LGL leukemia pathogenesis previously, we next designed primers for the secondary screening of the six exomes of STAT3 SH2 region from the remaining patients. Another recurrent somatic missense mutation (STAT3 Y640F) was identified in two additional patients. Thus, three out of nine LGL patients (33%) showed evidence of mutations in the STAT3 SH2 region. Both missense mutations found (D661V and Y640F) were located in the area of the SH2 domain known to mediate STAT3 protein dimerization and activation. The Y640F mutation alters a conserved tyrosine residue leading to a hyperactivating STAT protein (Scarzello et al. Mol Biol Cell, 2007) and was recently found in a human inflammatory hepatocellular adenoma causing cytokine-independent tyrosine phosphorylation and activation as well as cytokine-dependent hyperactivation of STAT3 (Pitali et al., J Exp Med, 2011). The D661V mutation has not been described previously. CONCLUSIONS: Our data imply for the first time that STAT3 is a common mutational target in LGL leukemia, revealing insights to the molecular pathogenesis of this rare disease. Known structural and functional data on STAT biology imply that the mutations are leading to STAT3 hyperactivation and could also confer ligand-independent signaling. While confirmatory data from a larger series of patients are necessary, our results pinpoint STAT3 mutations and aberrations in the STAT3 pathway as key pathogenetic events in true clonal LGL leukemia. Detection of STAT3 mutations could therefore be applied in the diagnostic assessment, disease stratification and therapeutic monitoring of LGL patients. Disclosures: Koskela: Novartis: Honoraria. Kuittinen:Roche: Consultancy. Porkka:Novartis: Honoraria; Bristol-Myers Squibb: Honoraria. Mustjoki:Novartis: Honoraria; Bristol-Myers Squibb: Honoraria.
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 2011
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    In: Blood, American Society of Hematology, Vol. 130, No. 24 ( 2017-12-14), p. 2682-2688
    Kurzfassung: HSCT represents an effective and definitive treatment of DADA2. HSCT can cure the immunological, hematological, and vascular phenotype of DADA2 with 100% survival at median follow-up of 18 months.
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 2017
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    In: Blood, American Society of Hematology, Vol. 120, No. 21 ( 2012-11-16), p. 288-288
    Kurzfassung: Abstract 288 Introduction: Recent genomic analyses of acute myeloid leukemia (AML) patients have provided new information on mutations contributing to the disease onset and progression. However, the genomic changes are often complex and highly diverse from one patient to another and often not actionable in clinical care. To rapidly identify novel patient-specific therapies, we developed a high-throughput drug sensitivity and resistance testing (DSRT) platform to experimentally validate therapeutic options for individual patients with relapsed AML. By integrating the results with exome and transcriptome sequencing plus proteomic analysis, we were able to define specific drug-sensitive subgroups of patients and explore predictive biomarkers. Methods: Ex vivo DSRT was implemented for 29 samples from 16 adult AML patients at the time of relapse and chemoresistance and from 5 healthy donors. Fresh mononuclear cells from bone marrow aspirates ( 〉 50% blast count) were screened against a comprehensive collection of cytotoxic chemotherapy agents (n=103) and targeted preclinical and clinical drugs (n=100, later 170). The drugs were tested over a 10,000-fold concentration range resulting in a dose-response curve for each compound and each leukemia sample. A leukemia-specific drug sensitivity score (sDSS) was derived from the area under each dose response curve in relation to the total area, and comparing leukemia samples with normal bone marrow results. The turnaround time for the DSRT assay was 4 days. All samples also underwent deep exome (40–100×) and transcriptome sequencing to identify somatic mutations and fusion transcripts, as well as phosphoproteomic array analysis to uncover active cell signaling pathways. Results: The drug sensitivity profiles of AML patient samples differed markedly from healthy bone marrow controls, with leukemia-specific responses mostly observed for molecularly targeted drugs. Individual AML patient samples clustered into distinct subgroups based on their chemoresponse profiles, thus suggesting that the subgroups were driven by distinct signaling pathways. Similarly, compounds clustered based on the response across the samples revealing functional groups of compounds of both expected and unexpected composition. Furthermore, subsets of patient samples stood out as highly sensitive to different compounds. Specifically, dasatinib, rapalogs, MEK inhibitors, ruxolitinib, sunitinib, sorafenib, ponatinib, foretinib and quizartinib were found to be selectively active in 5 (31%), 5 (31%), 4 (25%), 4 (25%), 3 (19%), 3 (19%), 2 (13%), 2 (13%), and 1 (6%) of the AML patients ex vivo, respectively. DSRT assays of serial samples from the same patient at different stages of leukemia progression revealed patterns of resistance to the clinically applied drugs, in conjunction with evidence of dynamic changes in the clonal genomic architecture. Emergence of vulnerabilities to novel pathway inhibitors was seen at the time of drug resistance, suggesting potential combinatorial or successive cycles of drugs to achieve remissions in an increasingly chemorefractory disease. Genomic and molecular profiling of the same patient samples not only highlighted potential biomarkers reflecting the ex vivo DSRT response patterns, but also made it possible to follow in parallel the drug sensitivities and the clonal progression of the disease in serial samples from the same patients. Summary: The comprehensive analysis of drug responses by DSRT in samples from human chemorefractory AML patients revealed a complex pattern of sensitivities to distinct inhibitors. Thus, these results suggest tremendous heterogeneity in drug response patterns and underline the relevance of individual ex vivo drug testing in selecting optimal therapies for patients (personalized medicine). Together with genomic and molecular profiling, the DSRT analysis resulted in a comprehensive view of the drug response landscape and the underlying molecular changes in relapsed AML. These data can readily be translated into the clinic via biomarker-driven stratified clinical trials. Disclosures: Mustjoki: Bristol-Myers Squibb: Honoraria, Research Funding; Novartis: Honoraria. Kallioniemi:Roche: Research Funding; Medisapiens: Membership on an entity's Board of Directors or advisory committees. Porkka:Bristol-Myers Squibb: Honoraria, Research Funding; Novartis: Honoraria, Research Funding.
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 2012
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    In: Blood, American Society of Hematology, Vol. 126, No. 23 ( 2015-12-03), p. 1024-1024
    Kurzfassung: Large granular lymphocyte (LGL) leukemia is a group of rare lymphoproliferative disorders which involve inappropriate clonal expansion of either cytotoxic T-lymphocytes (CTLs) or natural killer cells (NK). The usual age at onset is between 40 to 60 years. We here describe four very young patients showing LGL infiltration in the bone marrow (BM) and all diagnosed with primary immune deficiency. Patient 1 is a 13-year old male who presented with gingivostomatitis, but no severe infections, autoimmune disease or allergies. He had persistent leukopenia (1.9x109/L), neutropenia ( 〈 0.05x109/L), thrombocytopenia (60-80x109/L) and mild anemia. The BM showed myeloid maturation arrest and infiltration of LGL cells with NK cell phenotype (CD3-, CD2+, CD16+, CD56-/+, CD57-, CD4-, CD8-) at 50% of the BM cellularity. In peripheral blood (PB) T, B and NK cell counts were normal. However, low levels of monocytes (0.09x109/L), normal levels of monocytoid (2.7x106/L) and low levels of plasmacytoid (0.1x106/L) dendritic cells (DC) were detected. While germline whole exome sequencing (WES) did not identify mutations likely to cause the disease, targeted sequencing of GATA2 mRNA showed uniallelic GATA2 expression, confirming haploinsufficiency. Patient 2 is a 15-year old female who has neonatal diabetes, autoimmune desquamative interstitial pulmonary disease, autoimmune enteropathy, exocrine pancreatic insufficiency and delayed growth. She developed transfusion-dependent, Coombs-negative anemia at age of 15. In the PB, 50% of the lymphocytes were LGLs. BM showed pure red cell aplasia plus LGL infiltration of TCRgd positive T cells (CD3+, CD2+, CD5+, CD8-/+, CD4-/+, CD57+) at 43% of BM cellularity. Clonal TCRg rearrangement was detected. Hypogammaglobulinemia presented at age of 7. T, B and NK cell counts were low normal, but DCs were non-existent. WES and functional studies revealed a germline gain-of-function mutation of STAT3 gene. Patient 3 is 42-year old female who has had severe infections (bacterial, viral and protozoan) starting at the age of 4 months. From age of 9, autoimmune manifestations occurred with immune thrombocytopenia, neutropenia and anemia, and intensively positive rheumatoid factor. Since age of 17, CD8+ LGLs were detected in PB reaching level of 50% of lymphocytes. In the BM, CD3+CD5-CD56- T -lymphocyte infiltration with clonal TCRd rearrangement was detected. In her 30ies she developed pulmonal arterial hypertension and hypogammaglobulinemia (0.8 g/L). She has low counts of B cells (0.02x109/L), and monocytoid (1.9x106/L) and plasmacytoid (0) DCs. WES identified a homozygous germline missense mutation in CECR1 gene, leading to total loss-of-function of the encoded adenosine deaminase 2 (ADA2) protein. Patient 4 presented with waxing and waning skin nodules from age of 10 years, but no severe infections or allergies. At age of 26, she was diagnosed with hemolytic anemia with spherocytosis, splenomegaly and cholelithiasis. Five years later remarkable hepatomegaly, and clinical autoimmune manifestations with SLE-type skin lesions, autoimmune hemolytic anemia and iritis were observed. Complement C3 (0.17 g/l) and C4 ( 〈 0.02 g/L) and NK cell (0.081) levels were low, but CD3, CD8 and CD4 counts and IgM and IgG levels were increased. T-cell infiltration was shown in the skin nodules and liver. BM showed mildly decreased myelo- and erythropoiesis and T cell infiltration (CD3+, CD8+, CD7+, CD45RO+, BCL2+, CD56-) up to 70% of the BM cellularity consistent with LGL infiltration. WES identified the same germline missense mutation in CECR1 gene as seen in patient 3, and a functional analysis showed no ADA2 activity. We conclude that LGL lymphoproliferation in young patients is often a sign of underlying primary immunodeficiency, highlighting the need for detailed genetic studies in these cases. Table 1. Patient Age at LGL LGL in PB(109/L) LGL immune-phenotype Clonality BM LGL infiltration Clinical PID 1 13 0.38 NK NA 40% N,THepatomegaly GATA2 deficiency 2 15 1.79 CTL TCRg 43% AutoimmunityAHepatosplenomegaly STAT3 hyperactivation 3 17 1,49 CTL TCRd NA N,T, AAutoimmunityPulmonary arterial hypertension ADA2 deficiency 4 31 NA CTL TCRg weak 40% AutoimmunityHepatosplenomegalyHepatopulmonal syndrome ADA2 deficiency A, anemia; N, neutropenia, CTL, cytotoxic T cell; LGL, large granular lymphocyte; NK, natural killer cell; PID, primary immune deficiency; TCR, T cell receptor; T, thrombocytopenia Disclosures Mustjoki: Signe and Ane Gyllenberg Foundation: Research Funding; Finnish Cancer Institute: Research Funding; Sigrid Juselius Foundation: Research Funding; Academy of Finland: Research Funding; the Finnish Cancer Societies: Research Funding; Pfizer: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Siitonen:Pzizer: Other: charges of EAHAD congress 2015; Novartis: Other: charges of EHA congress 2015. Saarela:Roche: Honoraria.
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 2015
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    In: Blood, American Society of Hematology, Vol. 137, No. 15 ( 2021-04-15), p. 2033-2045
    Kurzfassung: Exocytosis of cytotoxic granules (CG) by lymphocytes is required for the elimination of infected and malignant cells. Impairments in this process underly a group of diseases with dramatic hyperferritinemic inflammation termed hemophagocytic lymphohistiocytosis (HLH). Although genetic and functional studies of HLH have identified proteins controlling distinct steps of CG exocytosis, the molecular mechanisms that spatiotemporally coordinate CG release remain partially elusive. We studied a patient exhibiting characteristic clinical features of HLH associated with markedly impaired cytotoxic T lymphocyte (CTL) and natural killer (NK) cell exocytosis functions, who beared biallelic deleterious mutations in the gene encoding the small GTPase RhoG. Experimental ablation of RHOG in a model cell line and primary CTLs from healthy individuals uncovered a hitherto unappreciated role of RhoG in retaining CGs in the vicinity of the plasma membrane (PM), a fundamental prerequisite for CG exocytotic release. We discovered that RhoG engages in a protein–protein interaction with Munc13-4, an exocytosis protein essential for CG fusion with the PM. We show that this interaction is critical for docking of Munc13-4+ CGs to the PM and subsequent membrane fusion and release of CG content. Thus, our study illuminates RhoG as a novel essential regulator of human lymphocyte cytotoxicity and provides the molecular pathomechanism behind the identified here and previously unreported genetically determined form of HLH.
    Materialart: Online-Ressource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Sprache: Englisch
    Verlag: American Society of Hematology
    Publikationsdatum: 2021
    ZDB Id: 1468538-3
    ZDB Id: 80069-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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