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1.
Clin Immunol ; 201: 30-34, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30776520

RESUMO

Severe combined immunodeficiencies (SCID) comprise a group of genetic diseases characterized by abrogated development of T lymphocytes. In some case reports of atypical SCID patients elevated proportions of γδ T lymphocytes have been reported. However, it is unknown whether these γδ T cells modulate or reflect the patient's clinical phenotype. We investigated the frequency of elevated γδ T cell proportions and associations with clinical disease manifestations in a cohort of 76 atypical SCID patients. Increased proportions of γδ T lymphocytes were present in approximately 60% of these patients. Furthermore, we identified positive correlations between elevated proportions of γδ T cells and the occurrence of CMV infections and autoimmune cytopenias. We discuss that CMV infections might trigger an expansion of γδ T lymphocytes, which could drive the development of autoimmune cytopenias. We advocate that atypical SCID patients should be screened for elevated proportions of γδ T lymphocytes, CMV infection and autoimmune cytopenias.

2.
J Clin Invest ; 128(12): 5489-5504, 2018 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-30395541

RESUMO

We report the molecular, cellular, and clinical features of 5 patients from 3 kindreds with biallelic mutations in the autosomal LIG1 gene encoding DNA ligase 1. The patients exhibited hypogammaglobulinemia, lymphopenia, increased proportions of circulating γδT cells, and erythrocyte macrocytosis. Clinical severity ranged from a mild antibody deficiency to a combined immunodeficiency requiring hematopoietic stem cell transplantation. Using engineered LIG1-deficient cell lines, we demonstrated chemical and radiation defects associated with the mutant alleles, which variably impaired the DNA repair pathway. We further showed that these LIG1 mutant alleles are amorphic or hypomorphic, and exhibited variably decreased enzymatic activities, which lead to premature release of unligated adenylated DNA. The variability of the LIG1 genotypes in the patients was consistent with that of their immunological and clinical phenotypes. These data suggest that different forms of autosomal recessive, partial DNA ligase 1 deficiency underlie an immunodeficiency of variable severity.

3.
Pediatr Nephrol ; 32(9): 1621-1624, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28488220

RESUMO

BACKGROUND: Immunodysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a rare primary immunodeficiency syndrome characterized by the development of multiple autoimmune disorders in affected individuals. Different forms of renal injury have been reported in IPEX syndrome, and membranous nephropathy (MN) is among the most common glomerulopathies found. However, the exact pathogenesis of MN in this setting has not been elucidated, and it is not clear whether it is part of the clinical spectrum of the disease or secondary to medications, infections or other concomitant insults. DIAGNOSIS/TREATMENT: We describe a child diagnosed with IPEX syndrome shortly after birth who presented with nephrotic syndrome at the age of 11 weeks. Renal biopsy revealed a MN with enhanced immunohistochemical staining for phospholipase A2 receptor (PLA2R). CONCLUSION: This is the first report of a PLA2R-positive MN in a patient with IPEX syndrome. We suggest that, in this context, MN results from an autoimmune process against podocytic antigens, namely PLA2R.

4.
J Exp Med ; 214(3): 623-637, 2017 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-28148688

RESUMO

We studied three patients with severe skeletal dysplasia, T cell immunodeficiency, and developmental delay. Whole-exome sequencing revealed homozygous missense mutations affecting exostosin-like 3 (EXTL3), a glycosyltransferase involved in heparan sulfate (HS) biosynthesis. Patient-derived fibroblasts showed abnormal HS composition and altered fibroblast growth factor 2 signaling, which was rescued by overexpression of wild-type EXTL3 cDNA. Interleukin-2-mediated STAT5 phosphorylation in patients' lymphocytes was markedly reduced. Interbreeding of the extl3-mutant zebrafish (box) with Tg(rag2:green fluorescent protein) transgenic zebrafish revealed defective thymopoiesis, which was rescued by injection of wild-type human EXTL3 RNA. Targeted differentiation of patient-derived induced pluripotent stem cells showed a reduced expansion of lymphohematopoietic progenitor cells and defects of thymic epithelial progenitor cell differentiation. These data identify EXTL3 mutations as a novel cause of severe immune deficiency with skeletal dysplasia and developmental delay and underline a crucial role of HS in thymopoiesis and skeletal and brain development.


Assuntos
Doenças do Desenvolvimento Ósseo/etiologia , Deficiências do Desenvolvimento/etiologia , Síndromes de Imunodeficiência/etiologia , Mutação , N-Acetilglucosaminiltransferases/genética , Animais , Pré-Escolar , Feminino , Heparitina Sulfato/fisiologia , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Lactente , Linfócitos/fisiologia , Peixe-Zebra
5.
Blood ; 128(6): 783-93, 2016 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-27301863

RESUMO

Primary immunodeficiency diseases comprise a group of heterogeneous genetic defects that affect immune system development and/or function. Here we use in vitro differentiation of human induced pluripotent stem cells (iPSCs) generated from patients with different recombination-activating gene 1 (RAG1) mutations to assess T-cell development and T-cell receptor (TCR) V(D)J recombination. RAG1-mutants from severe combined immunodeficient (SCID) patient cells showed a failure to sustain progression beyond the CD3(--)CD4(-)CD8(-)CD7(+)CD5(+)CD38(-)CD31(-/lo)CD45RA(+) stage of T-cell development to reach the CD3(-/+)CD4(+)CD8(+)CD7(+)CD5(+)CD38(+)CD31(+)CD45RA(-) stage. Despite residual mutant RAG1 recombination activity from an Omenn syndrome (OS) patient, similar impaired T-cell differentiation was observed, due to increased single-strand DNA breaks that likely occur due to heterodimers consisting of both an N-terminal truncated and a catalytically dead RAG1. Furthermore, deep-sequencing analysis of TCR-ß (TRB) and TCR-α (TRA) rearrangements of CD3(-)CD4(+)CD8(-) immature single-positive and CD3(+)CD4(+)CD8(+) double-positive cells showed severe restriction of repertoire diversity with preferential usage of few Variable, Diversity, and Joining genes, and skewed length distribution of the TRB and TRA complementary determining region 3 sequences from SCID and OS iPSC-derived cells, whereas control iPSCs yielded T-cell progenitors with a broadly diversified repertoire. Finally, no TRA/δ excision circles (TRECs), a marker of TRA/δ locus rearrangements, were detected in SCID and OS-derived T-lineage cells, consistent with a pre-TCR block in T-cell development. This study compares human T-cell development of SCID vs OS patients, and elucidates important differences that help to explain the wide range of immunologic phenotypes that result from different mutations within the same gene of various patients.


Assuntos
Proteínas de Homeodomínio/genética , Células-Tronco Pluripotentes Induzidas/patologia , Imunodeficiência Combinada Severa/genética , Imunodeficiência Combinada Severa/patologia , Linfócitos T/patologia , Células Cultivadas , Quebras de DNA , Genes RAG-1 , Humanos , Lactente , Mutação , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Recombinação V(D)J
6.
J Clin Immunol ; 36(4): 341-53, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27063650

RESUMO

PURPOSE: DNA Ligase 4 (LIG4) is a key factor in the non-homologous end-joining (NHEJ) DNA double-strand break repair pathway needed for V(D)J recombination and the generation of the T cell receptor and immunoglobulin molecules. Defects in LIG4 result in a variable syndrome of growth retardation, pancytopenia, combined immunodeficiency, cellular radiosensitivity, and developmental delay. METHODS: We diagnosed a patient with LIG4 syndrome by radiosensitivity testing on peripheral blood cells, and established that two of her four healthy siblings carried the same compound heterozygous LIG4 mutations. An extensive analysis of the immune phenotype, cellular radiosensitivity, telomere length, and T and B cell antigen receptor repertoire was performed in all siblings. RESULTS: In the three genotypically affected individuals, variable severities of radiosensitivity, alterations of T and B cell counts with an increased percentage of memory cells, and hypogammaglobulinemia, were noticed. Analysis of T and B cell antigen receptor repertoires demonstrated increased usage of alternative microhomology-mediated end-joining (MHMEJ) repair, leading to diminished N nucleotide addition and shorter CDR3 length. However, overall repertoire diversity was preserved. CONCLUSIONS: We demonstrate that LIG4 syndrome presents with high clinical variability even within the same family, and that distinctive immunologic abnormalities may be observed also in yet asymptomatic individuals.


Assuntos
DNA Ligase Dependente de ATP/genética , Síndromes de Imunodeficiência , Adolescente , Adulto , Agamaglobulinemia/genética , Agamaglobulinemia/imunologia , Linhagem Celular , Células Cultivadas , Criança , Feminino , Fibroblastos/efeitos da radiação , Granulócitos/efeitos da radiação , Humanos , Síndromes de Imunodeficiência/genética , Síndromes de Imunodeficiência/imunologia , Leucócitos Mononucleares/citologia , Contagem de Linfócitos , Subpopulações de Linfócitos/imunologia , Masculino , Mutação , Radiação Ionizante , Adulto Jovem
8.
J Immunol ; 195(12): 5608-15, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26546606

RESUMO

Nonhomologous end-joining (NHEJ) is one of the major DNA double-strand break repair pathways in mammalian cells and is required for both V(D)J recombination and class switch recombination (CSR), two Ig gene-diversification processes occurring during B cell development. DNA-dependent protein kinase, catalytic subunit (DNA-PKcs) is a component of the classical NHEJ machinery and has a critical function during V(D)J recombination. However, its role in CSR has been controversial. In this study, we examined the pattern of recombination junctions from in vivo-switched B cells from two DNA-PKcs-deficient patients. One of them harbored mutations that did not affect DNA-PKcs kinase activity but caused impaired Artemis activation; the second patient had mutations resulting in diminished DNA-PKcs protein expression and kinase activity. These results were compared with those from DNA-PKcs-deficient mouse B cells. A shift toward the microhomology-based alternative end-joining at the recombination junctions was observed in both human and mouse B cells, suggesting that the classical NHEJ pathway is impaired during CSR when DNA-PKcs is defective. Furthermore, cells from the second patient showed additional or more severe alterations in CSR and/or NHEJ, which may suggest that DNA-PKcs and/or its kinase activity have additional, Artemis-independent functions during these processes.


Assuntos
Linfócitos B/imunologia , Proteína Quinase Ativada por DNA/metabolismo , Proteínas de Ligação a DNA/metabolismo , Endonucleases/metabolismo , Switching de Imunoglobulina , Síndromes de Imunodeficiência/imunologia , Proteínas Nucleares/metabolismo , Animais , Diferenciação Celular , Proteína Quinase Ativada por DNA/genética , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica/genética , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos SCID , Mutação/genética , Proteínas Nucleares/genética
9.
J Exp Med ; 212(8): 1185-202, 2015 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-26150473

RESUMO

Adenylate kinases (AKs) are phosphotransferases that regulate the cellular adenine nucleotide composition and play a critical role in the energy homeostasis of all tissues. The AK2 isoenzyme is expressed in the mitochondrial intermembrane space and is mutated in reticular dysgenesis (RD), a rare form of severe combined immunodeficiency (SCID) in humans. RD is characterized by a maturation arrest in the myeloid and lymphoid lineages, leading to early onset, recurrent, and overwhelming infections. To gain insight into the pathophysiology of RD, we studied the effects of AK2 deficiency using the zebrafish model and induced pluripotent stem cells (iPSCs) derived from fibroblasts of an RD patient. In zebrafish, Ak2 deficiency affected hematopoietic stem and progenitor cell (HSPC) development with increased oxidative stress and apoptosis. AK2-deficient iPSCs recapitulated the characteristic myeloid maturation arrest at the promyelocyte stage and demonstrated an increased AMP/ADP ratio, indicative of an energy-depleted adenine nucleotide profile. Antioxidant treatment rescued the hematopoietic phenotypes in vivo in ak2 mutant zebrafish and restored differentiation of AK2-deficient iPSCs into mature granulocytes. Our results link hematopoietic cell fate in AK2 deficiency to cellular energy depletion and increased oxidative stress. This points to the potential use of antioxidants as a supportive therapeutic modality for patients with RD.


Assuntos
Adenilato Quinase/metabolismo , Células-Tronco Hematopoéticas/fisiologia , Leucopenia/enzimologia , Leucopenia/fisiopatologia , Estresse Oxidativo/fisiologia , Células-Tronco Pluripotentes/fisiologia , Imunodeficiência Combinada Severa/enzimologia , Imunodeficiência Combinada Severa/fisiopatologia , Laranja Acridina , Adenilato Quinase/deficiência , Animais , Antioxidantes/farmacologia , Apoptose/fisiologia , Compostos Azo , Sequência de Bases , Diferenciação Celular/efeitos dos fármacos , Biologia Computacional , Primers do DNA/genética , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Dados de Sequência Molecular , Naftalenos , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Peixe-Zebra
10.
N Engl J Med ; 372(25): 2409-22, 2015 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-26083206

RESUMO

Background Combined immunodeficiencies are marked by inborn errors of T-cell immunity in which the T cells that are present are quantitatively or functionally deficient. Impaired humoral immunity is also common. Patients have severe infections, autoimmunity, or both. The specific molecular, cellular, and clinical features of many types of combined immunodeficiencies remain unknown. Methods We performed genetic and cellular immunologic studies involving five unrelated children with early-onset invasive bacterial and viral infections, lymphopenia, and defective T-cell, B-cell, and natural killer (NK)-cell responses. Two patients died early in childhood; after allogeneic hematopoietic stem-cell transplantation, the other three had normalization of T-cell function and clinical improvement. Results We identified biallelic mutations in the dedicator of cytokinesis 2 gene (DOCK2) in these five patients. RAC1 activation was impaired in the T cells. Chemokine-induced migration and actin polymerization were defective in the T cells, B cells, and NK cells. NK-cell degranulation was also affected. Interferon-α and interferon-λ production by peripheral-blood mononuclear cells was diminished after viral infection. Moreover, in DOCK2-deficient fibroblasts, viral replication was increased and virus-induced cell death was enhanced; these conditions were normalized by treatment with interferon alfa-2b or after expression of wild-type DOCK2. Conclusions Autosomal recessive DOCK2 deficiency is a new mendelian disorder with pleiotropic defects of hematopoietic and nonhematopoietic immunity. Children with clinical features of combined immunodeficiencies, especially with early-onset, invasive infections, may have this condition. (Supported by the National Institutes of Health and others.).


Assuntos
Doenças Genéticas Inatas/genética , Fatores de Troca do Nucleotídeo Guanina/genética , Síndromes de Imunodeficiência/genética , Mutação , Linfócitos T/imunologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Pré-Escolar , Evolução Fatal , Feminino , Genes Recessivos , Doenças Genéticas Inatas/terapia , Fatores de Troca do Nucleotídeo Guanina/deficiência , Transplante de Células-Tronco Hematopoéticas , Humanos , Síndromes de Imunodeficiência/terapia , Lactente , Células Matadoras Naturais/imunologia , Masculino , Linhagem , Linfócitos T/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo
11.
J Allergy Clin Immunol ; 136(1): 140-150.e7, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25917813

RESUMO

BACKGROUND: The endonuclease ARTEMIS, which is encoded by the DCLRE1C gene, is a component of the nonhomologous end-joining pathway and participates in hairpin opening during the V(D)J recombination process and repair of a subset of DNA double-strand breaks. Patients with ARTEMIS deficiency usually present with severe combined immunodeficiency (SCID) and cellular radiosensitivity, but hypomorphic mutations can cause milder phenotypes (leaky SCID). OBJECTIVE: We sought to correlate the functional effect of human DCLRE1C mutations on phenotypic presentation in patients with ARTEMIS deficiency. METHODS: We studied the recombination and DNA repair activity of 41 human DCLRE1C mutations in Dclre1c(-/-) v-abl kinase-transformed pro-B cells retrovirally engineered with a construct that allows quantification of recombination activity by means of flow cytometry. For assessment of DNA repair efficacy, resolution of γH2AX accumulation was studied after ionizing radiation. RESULTS: Low or absent activity was detected for mutations causing a typical SCID phenotype. Most of the patients with leaky SCID were compound heterozygous for 1 loss-of-function and 1 hypomorphic allele, with significant residual levels of recombination and DNA repair activity. Deletions disrupting the C-terminus result in truncated but partially functional proteins and are often associated with leaky SCID. Overexpression of hypomorphic mutants might improve the functional defect. CONCLUSIONS: Correlation between the nature and location of DCLRE1C mutations, functional activity, and the clinical phenotype has been observed. Hypomorphic variants that have been reported in the general population can be disease causing if combined in trans with a loss-of-function allele. Therapeutic strategies aimed at inducing overexpression of hypomorphic alleles might be beneficial.


Assuntos
Linfócitos B/fisiologia , Mutação/genética , Proteínas Nucleares/genética , Imunodeficiência Combinada Severa/genética , Adolescente , Adulto , Alelos , Linfócitos B/efeitos da radiação , Linhagem Celular Transformada , Criança , Pré-Escolar , Análise Mutacional de DNA , Reparo do DNA/genética , Endonucleases , Heterozigoto , Histonas/metabolismo , Humanos , Lactente , Recém-Nascido , Masculino , Proteínas Oncogênicas v-abl/genética , Proteínas Oncogênicas v-abl/metabolismo , Fenótipo , Tolerância a Radiação/genética , Radiação Ionizante , Recombinação V(D)J/genética , Adulto Jovem
12.
Proc Natl Acad Sci U S A ; 111(24): 8889-94, 2014 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-24889605

RESUMO

Nonhomologous end-joining (NHEJ) is a key pathway for efficient repair of DNA double-strand breaks (DSBs) and V(D)J recombination. NHEJ defects in humans cause immunodeficiency and increased cellular sensitivity to ionizing irradiation (IR) and are variably associated with growth retardation, microcephaly, and neurodevelopmental delay. Repair of DNA DSBs is important for reprogramming of somatic cells into induced pluripotent stem cells (iPSCs). To compare the specific contribution of DNA ligase 4 (LIG4), Artemis, and DNA-protein kinase catalytic subunit (PKcs) in this process and to gain insights into phenotypic variability associated with these disorders, we reprogrammed patient-derived fibroblast cell lines with NHEJ defects. Deficiencies of LIG4 and of DNA-PK catalytic activity, but not Artemis deficiency, were associated with markedly reduced reprogramming efficiency, which could be partially rescued by genetic complementation. Moreover, we identified increased genomic instability in LIG4-deficient iPSCs. Cell cycle synchronization revealed a severe defect of DNA repair and a G0/G1 cell cycle arrest, particularly in LIG4- and DNA-PK catalytically deficient iPSCs. Impaired myeloid differentiation was observed in LIG4-, but not Artemis- or DNA-PK-mutated iPSCs. These results indicate a critical importance of the NHEJ pathway for somatic cell reprogramming, with a major role for LIG4 and DNA-PKcs and a minor, if any, for Artemis.


Assuntos
Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades , Células-Tronco Pluripotentes Induzidas/citologia , Catálise , Ciclo Celular , Diferenciação Celular , Linhagem Celular , Linhagem da Célula , DNA Ligase Dependente de ATP , DNA Ligases/metabolismo , Proteína Quinase Ativada por DNA/genética , Endonucleases , Fibroblastos/metabolismo , Fibroblastos/patologia , Células-Tronco Hematopoéticas/citologia , Humanos , Mutação , Proteínas Nucleares/metabolismo , Fenótipo
13.
Clin Immunol ; 150(1): 43-50, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24333532

RESUMO

Loeys-Dietz syndrome (LDS) is a connective tissue disorder caused by monoallelic mutations in TGFBR1 and TGFBR2, which encode for subunits of the transforming growth factor beta (TGFß) receptor. Affected patients are identified by vascular aneurysms with tortuosity and distinct morphological presentations similar to Marfan syndrome; however, an additional predisposition towards asthma and allergy has recently been found. We describe two patients with a novel missense mutation in TGFBR1 presenting with highly elevated levels of IgE and severe eczema similar to autosomal-dominant Hyper-IgE syndrome (HIES). Mild allergic manifestations with normal up to moderately increased IgE were observed in 3 out of 6 additional LDS patients. A comparison of this cohort with 4 HIES patients illustrates the significant overlap of both syndromes including eczema and elevated IgE as well as skeletal and connective tissue manifestations.


Assuntos
Eczema/sangue , Imunoglobulina E/sangue , Síndrome de Loeys-Dietz/sangue , Proteínas Serina-Treonina Quinases/genética , Receptores de Fatores de Crescimento Transformadores beta/genética , Adolescente , Adulto , Linfócitos T CD4-Positivos/imunologia , Criança , Pré-Escolar , Doenças do Tecido Conjuntivo/sangue , Doenças do Tecido Conjuntivo/genética , Doenças do Tecido Conjuntivo/imunologia , Citocinas/imunologia , Eczema/genética , Eczema/imunologia , Feminino , Humanos , Síndrome de Job/sangue , Síndrome de Job/genética , Síndrome de Job/imunologia , Síndrome de Loeys-Dietz/genética , Síndrome de Loeys-Dietz/imunologia , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Proteínas Serina-Treonina Quinases/imunologia , Receptor do Fator de Crescimento Transformador beta Tipo I , Receptores de Fatores de Crescimento Transformadores beta/imunologia , Fator de Transcrição STAT3/sangue , Fator de Transcrição STAT3/deficiência , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/imunologia , Fator de Crescimento Transformador beta/imunologia
14.
Curr Opin Immunol ; 24(5): 617-24, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22841347

RESUMO

The advent of reprogramming technology has greatly advanced the field of stem cell biology and nurtured our hope to create patient specific renewable stem cell sources. While the number of reports of disease specific induced pluripotent stem cells is continuously rising, the field becomes increasingly more aware that induced pluripotent stem cells are not as similar to embryonic stem cells as initially assumed. Our state of the art understanding of human induced pluripotent stem cells, their capacity, their limitations and their promise as it pertains to the study and treatment of primary immunodeficiencies, is the content of this review.


Assuntos
Diferenciação Celular/imunologia , Síndromes de Imunodeficiência/patologia , Síndromes de Imunodeficiência/terapia , Células-Tronco Pluripotentes/fisiologia , Células-Tronco Pluripotentes/transplante , Medicina Regenerativa/métodos , Animais , Transplante de Células/métodos , Transplante de Células/tendências , Modelos Animais de Doenças , Humanos , Síndromes de Imunodeficiência/fisiopatologia , Células-Tronco Pluripotentes/patologia , Medicina Regenerativa/tendências
16.
Clin Immunol ; 141(1): 73-82, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21664875

RESUMO

Hypomorphic mutations in genes associated with severe combined immunodeficiency (SCID) or Omenn syndrome can also cause milder immunodeficiencies. We report 10 new patients with such "atypical" SCID and summarize 63 patients from the literature. The patient groups with T(low)B(low) (n=28), T(low)B(+) (n=16) and ADA (n=29) SCID variants had similar infection profiles but differed in the frequency of immune dysregulation, which was observed predominantly in patients with recombination defects. Most immunological parameters were remarkably similar in the three groups. Of note, 19/68 patients with "atypical" SCID had normal T cell counts, 48/68 had normal IgG and 23/46 had at least one normal specific antibody titer. Elevated IgE was a characteristic feature of ADA deficiency. This overview characterizes "atypical" SCID as a distinct disease with immune dysregulation in addition to infection susceptibility. Lymphopenia, reduced naïve T cells and elevated IgE are suggestive, but not consistent features of the disease.


Assuntos
Imunodeficiência Combinada Severa/imunologia , Adenosina Desaminase/deficiência , Adenosina Desaminase/genética , Adenosina Desaminase/imunologia , Adolescente , Adulto , Agamaglobulinemia/complicações , Agamaglobulinemia/genética , Agamaglobulinemia/imunologia , Doenças Autoimunes/complicações , Doenças Autoimunes/genética , Doenças Autoimunes/imunologia , Linfócitos B/imunologia , Criança , Pré-Escolar , Estudos de Coortes , Humanos , Imunoglobulina E/sangue , Recém-Nascido , Infecção/etiologia , Mutação , Imunodeficiência Combinada Severa/complicações , Imunodeficiência Combinada Severa/genética , Imunodeficiência Combinada Severa/terapia , Linfócitos T/imunologia , Resultado do Tratamento
17.
Peptides ; 27(12): 3100-6, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16963160

RESUMO

Antimicrobial peptides (AMPs) and mucins are components of airway secretions and both contribute to the innate host defense system. At neutral pH, AMPs are positively charged, mucins negatively. It was the aim of the study to test whether these opposite charges result in interactions between AMPs and mucins. We measured binding of mucins isolated from porcine gastric mucosa to the cathelicidin LL-37 coated to multiwell plates and found that LL-37 electrostatically interacts with mucins. Circular dichroism spectra of the peptide revealed the induction of alpha-helical conformation by mucins. Addition of mucins to solutions of LL-37 significantly decreased the antimicrobial activity of the peptide against Pseudomonas aeruginosa and Streptococcus pneumoniae. We then tested whether LL-37 is bound to mucins in airway secretions from human subjects and found that a significant proportion of the peptide and its propeptide are bound to high molecular weight components. Together these data show that cationic AMPs interact with anionic mucins in airway secretions. Functions of AMPs are modulated by this interaction.


Assuntos
Peptídeos Catiônicos Antimicrobianos/metabolismo , Muco/metabolismo , Mucosa Respiratória/metabolismo , Adulto , Animais , Humanos , Suínos
18.
J Immunol ; 177(3): 1833-7, 2006 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-16849494

RESUMO

The innate immune system of the lung is a multicomponent host defense system and in addition has an instructing role in regulating the quality and quantity of the adaptive immune response. When the interaction between innate and adaptive immunity is disturbed, pathological conditions such as asthma can develop. It was the aim of the study to investigate the effect of the allergic inflammation of the lung on the innate host defense during bacterial infection. Human bronchial epithelial cells were preincubated with Th2 cytokines and infected with Pseudomonas aeruginosa. The effect of the Th2 cytokines on the mRNA levels of antimicrobial peptides and the antimicrobial activity of HBEC was determined. To investigate the influence of an allergic inflammation on pulmonary host defense in vivo, mice sensitized and challenged with OVA were infected with P. aeruginosa, and the number of viable bacteria in the lungs was determined together with markers of inflammation like cytokines and antimicrobial peptides. Exposure of airway epithelial cells to Th2 cytokines resulted in a significantly decreased antimicrobial activity of the cells and in suppressed mRNA levels of the antimicrobial peptide human beta-defensin 2. Furthermore, mice with allergic airway inflammation had significantly more viable bacteria in their lungs after infection. This was consistent with reduced levels of proinflammatory cytokines and of the antimicrobial peptide cathelin-related antimicrobial peptide. These results show that an allergic airway inflammation suppresses the innate antimicrobial host defense. The adaptive immune system modulates the functions of the pulmonary innate immune system.


Assuntos
Peptídeos Catiônicos Antimicrobianos/antagonistas & inibidores , Imunossupressão , Pulmão/imunologia , Pulmão/patologia , Hipersensibilidade Respiratória/imunologia , Hipersensibilidade Respiratória/microbiologia , Alérgenos/administração & dosagem , Alérgenos/imunologia , Animais , Peptídeos Catiônicos Antimicrobianos/biossíntese , Peptídeos Catiônicos Antimicrobianos/fisiologia , Linhagem Celular , Citocinas/fisiologia , Feminino , Humanos , Imunidade Inata , Inflamação/imunologia , Inflamação/microbiologia , Pulmão/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Ovalbumina/administração & dosagem , Ovalbumina/imunologia , Pneumonia Bacteriana/imunologia , Pneumonia Bacteriana/microbiologia , Pneumonia Bacteriana/patologia , Pseudomonas aeruginosa/imunologia , Hipersensibilidade Respiratória/patologia , Mucosa Respiratória/imunologia , Mucosa Respiratória/microbiologia , Mucosa Respiratória/patologia , Células Th2/imunologia , Células Th2/metabolismo , Células Th2/microbiologia
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