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1.
Nat Immunol ; 23(8): 1256-1272, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35902638

RESUMO

The recombination-activating genes (RAG) 1 and 2 are indispensable for diversifying the primary B cell receptor repertoire and pruning self-reactive clones via receptor editing in the bone marrow; however, the impact of RAG1/RAG2 on peripheral tolerance is unknown. Partial RAG deficiency (pRD) manifesting with late-onset immune dysregulation represents an 'experiment of nature' to explore this conundrum. By studying B cell development and subset-specific repertoires in pRD, we demonstrate that reduced RAG activity impinges on peripheral tolerance through the generation of a restricted primary B cell repertoire, persistent antigenic stimulation and an inflammatory milieu with elevated B cell-activating factor. This unique environment gradually provokes profound B cell dysregulation with widespread activation, remarkable extrafollicular maturation and persistence, expansion and somatic diversification of self-reactive clones. Through the model of pRD, we reveal a RAG-dependent 'domino effect' that impacts stringency of tolerance and B cell fate in the periphery.


Assuntos
Linfócitos B , Proteínas de Ligação a DNA , Proteínas de Homeodomínio , Proteínas Nucleares , Diferenciação Celular , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Proteínas de Homeodomínio/genética , Humanos , Tolerância Imunológica , Contagem de Linfócitos , Proteínas Nucleares/deficiência
2.
J Allergy Clin Immunol ; 141(1): 311-321.e10, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28624612

RESUMO

BACKGROUND: Mast cells (MCs), the primary effector cell of the atopic response, participate in immune defense at host/environment interfaces, yet the mechanisms by which they interact with CD4+ T cells has been controversial. OBJECTIVE: We used in situ-matured primary human MCs and matched CD4+ T cells to diligently assess the ability of MCs to act as antigen-presenting cells. METHODS: We examined mature human skin-derived MCs using flow cytometry for expression of antigen-presenting molecules, for their ability to stimulate CD4+ T cells to express CD25 and proliferate when exposed to superantigen or to cytomegalovirus (CMV) antigen using matched T cells and MCs from CMV-seropositive or CMV-seronegative donors, and for antigen uptake. Subcellular localization of antigen, HLA molecules, and tryptase was analyzed by using structured illumination microscopy. RESULTS: Our data show that IFN-γ induces HLA class II, HLA-DM, CD80, and CD40 expression on MCs, whereas MCs take up soluble and particulate antigens in an IFN-γ-independent manner. IFN-γ-primed MCs guide activation of T cells by Staphylococcus aureus superantigen and, when preincubated with CMV antigens, induce a recall CD4+ TH1 proliferation response only in CMV-seropositive donors. MCs co-opt their secretory granules for antigen processing and presentation. Consequently, MC degranulation increases surface delivery of HLA class II/peptide, further enhancing stimulation of T-cell proliferation. CONCLUSIONS: IFN-γ primes human MCs to activate T cells through superantigen and to present CMV antigen to TH1 cells, co-opting MC secretory granules for antigen processing and presentation and creating a feed-forward loop of T-cell-MC cross-activation.


Assuntos
Apresentação de Antígeno , Linfócitos T CD4-Positivos/imunologia , Mastócitos/imunologia , Apresentação de Antígeno/imunologia , Células Apresentadoras de Antígenos/imunologia , Antígenos Virais/imunologia , Transporte Biológico , Biomarcadores , Linfócitos T CD4-Positivos/metabolismo , Comunicação Celular , Células Cultivadas , Dinaminas , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Imunofenotipagem , Interferon gama/metabolismo , Mastócitos/metabolismo , Especificidade do Receptor de Antígeno de Linfócitos T
3.
Allergy Asthma Clin Immunol ; 19(1): 68, 2023 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-37550789

RESUMO

BACKGROUND: Wiskott-Aldrich syndrome (WAS) is an X-linked primary immunodeficiency caused by mutations in the WAS gene that leads to increased susceptibility to infections, thrombocytopenia, eczema, malignancies, and autoimmunity. Central nervous system (CNS) autoimmune manifestations are uncommon. CASE PRESENTATION: We describe the case of a five-year-old boy with refractory thrombocytopenia and iron deficiency anemia who developed relapsing bilateral optic neuritis. Myelin oligodendrocyte glycoprotein antibody (MOG-IgG) via serum fluorescence-activated cell sorting assay was positive (titer 1:100), confirming a diagnosis of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). At age six, molecular panel testing for genes associated with primary immunodeficiency identified a missense WAS gene variant. He was subsequently found to have decreased WAS protein expression, consistent with a diagnosis of WAS. CONCLUSIONS: This case expands the reported spectrum of CNS autoimmunity associated with WAS and may help to inform long-term therapeutic options.

4.
NEJM Evid ; 2(6): EVIDoa2200339, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38320129

RESUMO

BACKGROUND: Indolent systemic mastocytosis (ISM) is a clonal mast-cell disease driven by the KIT D816V mutation. We assessed the efficacy and safety of avapritinib versus placebo, both with best supportive care, in patients with ISM. METHODS: We randomized patients with moderate to severe ISM (total symptom score [TSS] of ≥28; scores range from 0 to 110, with higher numbers indicating more severe symptoms) two to one to avapritinib 25 mg once daily (n=141) or placebo (n=71). The primary end point was mean change in TSS based on the 14-day average of patient-reported severity of 11 symptoms. Secondary end points included reductions in serum tryptase and blood KIT D816V variant allele fraction (≥50%), reductions in TSS (≥50% and ≥30%), reduction in bone marrow mast cells (≥50%), and quality of life measures. RESULTS: From baseline to week 24, avapritinib-treated patients had a decrease of 15.6 points (95% CI, −18.6 to −12.6) in TSS compared to a decrease of 9.2 points (−13.1 to −5.2) in the placebo group; P<0.003. From baseline to Week 24, 76/141 patients (54%; 45% to 62%) in the avapritinib group compared to 0/71 patients in the placebo group achieved a ≥50% reduction in serum tryptase level; P<0.001. Edema and increases in alkaline phosphatase were more common with avapritinib than placebo; there were few treatment discontinuations because of adverse events. CONCLUSIONS: In this trial, avapritinib was superior to placebo in reducing uncontrolled symptoms and mast-cell burden in patients with ISM. The long-term safety and efficacy of this approach for patients with ISM remain the focus of the ongoing trial. (Funded by Blueprint Medicines Corporation; ClinicalTrials.gov number, NCT03731260.)


Assuntos
Mastocitose Sistêmica , Humanos , Mastocitose Sistêmica/diagnóstico , Pirazóis/uso terapêutico , Pirróis/uso terapêutico , Triazinas/uso terapêutico
6.
J Dermatol Sci ; 45(1): 23-30, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17123788

RESUMO

BACKGROUND: To understand the behavioral biology of Langerhans cells (LCs), we recently recorded time-lapse images of LCs in the knock-in mice expressing the I-Abeta chain tagged with the enhanced green fluorescence protein (EGFP). EGFP(+) LCs showed relatively limited motility in the steady state, whereas topical application of dinitrofluorobenzene (DNFB) markedly augmented a unique movement of dendrites characterized by rhythmic extension and retraction, termed dSEARCH, and triggered amoeba-like lateral migration of cell bodies. OBJECTIVE: To define underlying mechanisms by which hapten treatment alters LC behaviors. METHODS: The I-Abeta-EGFP mice received subcutaneous (s.c.) injection of recombinant IL-1alpha or TNFalpha (50 ng/animal) and dynamic behaviors of EGFP(+) LCs were recorded by time-lapse confocal microscopy at several time points to measure their dSEARCH activities and lateral migration. In a different set of experiments, IL-1 receptor antagonist (IL-1Ra) or soluble TNF receptor-2 (sTNFR2) (0.5 microg/animal) was s.c. injected into the ear skin 30 min before topical application of DNFB, and LC behaviors analyzed 30 h later. RESULTS: Local injection of IL-1alpha or TNFalpha induced significant, albeit modest, augmentation of both dSEARCH and lateral migration. Co-injection of TNFalpha and IL-1alpha further exacerbated motile activities in a synergistic manner by similar magnitudes observed after DNFB application. Conversely, DNFB-induced behavioral changes were inhibited completely by local injection of IL-1Ra or sTNFR2. CONCLUSION: IL-1 and TNFalpha serve as equally important mediators of hapten-induced alteration of LC behaviors. Motile activities of epidermal LCs are reprogrammed by selected cytokines known to be produced by keratinocytes under pathological conditions.


Assuntos
Movimento Celular/fisiologia , Haptenos/administração & dosagem , Interleucina-1alfa/fisiologia , Células de Langerhans/efeitos dos fármacos , Células de Langerhans/fisiologia , Fator de Necrose Tumoral alfa/fisiologia , Administração Tópica , Animais , Movimento Celular/efeitos dos fármacos , Dinitrofluorbenzeno/antagonistas & inibidores , Dinitrofluorbenzeno/farmacologia , Sinergismo Farmacológico , Corantes Fluorescentes , Proteínas de Fluorescência Verde , Haptenos/farmacologia , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/metabolismo , Injeções Subcutâneas , Interleucina-1alfa/administração & dosagem , Interleucina-1alfa/antagonistas & inibidores , Interleucina-1alfa/farmacologia , Cinética , Camundongos , Camundongos Transgênicos , Proteínas Recombinantes/farmacologia , Fatores de Tempo , Fator de Necrose Tumoral alfa/administração & dosagem , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/farmacologia
7.
Immunol Allergy Clin North Am ; 37(2): 431-448, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28366486

RESUMO

This article presents an overview of future uses for biologic therapies in the treatment of immunologic and allergic conditions. Discussion is centered on the use of existing therapies outside of their current indication or on new therapies that are close to approval. This information may help familiarize practicing allergists and immunologists with therapies they may soon encounter in their practice as well as help identify conditions and treatments that will require further study in the near future.


Assuntos
Terapia Biológica , Doenças do Sistema Imunitário/terapia , Anticorpos Anti-Idiotípicos/farmacologia , Anticorpos Anti-Idiotípicos/uso terapêutico , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/uso terapêutico , Produtos Biológicos/farmacologia , Produtos Biológicos/uso terapêutico , Terapia Biológica/métodos , Terapia Biológica/tendências , Citocinas/antagonistas & inibidores , Citocinas/metabolismo , Dessensibilização Imunológica , Gerenciamento Clínico , Humanos , Doenças do Sistema Imunitário/diagnóstico , Doenças do Sistema Imunitário/imunologia , Doenças do Sistema Imunitário/metabolismo , Terapia de Alvo Molecular , Receptores de Citocinas/antagonistas & inibidores , Receptores de Citocinas/metabolismo , Transdução de Sinais/efeitos dos fármacos
8.
J Invest Dermatol ; 126(4): 787-96, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16439974

RESUMO

Pathological stimuli provoke coordinated changes in gene expression, surface phenotype, and function of dendritic cells (DCs), thereby facilitating the induction of adaptive immune responses. This concept of DC maturation was established mainly by studying epidermal Langerhans cells (LCs), a prototypic immature DC subset at the environmental interface. Taking advantage of I-Abeta-enhanced green fluorescent protein (EGFP) knock-in mice in which LCs can be visualized in intact skin, we recorded the dynamic movement of EGFP+ LCs by time-lapse confocal microscopy. LCs exhibited a unique behavior, termed dendrite surveillance extension and retraction cycling habitude (dSEARCH), characterized by rhythmic extension and retraction of dendrites through intercellular spaces between keratinocytes. When monitored after skin organ culture or subcutaneous injection of tumor necrosis factor alpha, LCs showed amplified dSEARCH and amoeba-like lateral migration between keratinocytes. Intravital imaging experiments further revealed steady-state dSEARCH motion in 5-10% of LCs. Topical application of a reactive hapten, DNFB, augmented dSEARCH and triggered lateral migration of LC in vivo. These observations introduce a new concept that in situ maturation of LCs is further accompanied by coordinated reprogramming of motile activities.


Assuntos
Comunicação Celular , Diferenciação Celular , Células Epidérmicas , Células de Langerhans/citologia , Células de Langerhans/imunologia , Animais , Movimento Celular , Epiderme/imunologia , Proteínas de Fluorescência Verde/análise , Proteínas de Fluorescência Verde/genética , Antígenos de Histocompatibilidade Classe II/análise , Antígenos de Histocompatibilidade Classe II/genética , Células de Langerhans/efeitos dos fármacos , Camundongos , Camundongos Mutantes , Fator de Necrose Tumoral alfa/farmacologia
9.
Ocul Surf ; 2(1): 10-20, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17216072

RESUMO

This paper reviews new developments in microscopy that combine gene transfer technology, multiphoton confocal fluorescence microscopy, live cell imaging and digital imaging techniques that provide unique insights into the complex physiological processes involved in tissue function at the cellular and subcellular level. The evolution of this novel, new technology is discussed with particular attention to earlier achievements in noninvasive ocular surface imaging. The practical basis of confocal microscopy, multiphoton confocal fluorescence microscopy, and the vital fluorescent labeling of cells in living tissues are also discussed. Additionally, one application using retroviral gene transfer to express enhanced green fluorescent protein in living wound healing fibroblasts is presented as an example of how living biology can be studied in situ in four dimensions (x, y, z, time).

10.
Immunology ; 120(4): 556-72, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17250587

RESUMO

Langerhans cells (LCs) represent a special subset of immature dendritic cells (DCs) that reside in epithelial tissues at the environmental interfaces. Although dynamic interactions of mature DCs with T cells have been visualized in lymph nodes, the cellular behaviours linked with the surveillance of tissues for pathogenic signals, an important function of immature DCs, remain unknown. To visualize LCs in situ, bone marrow cells from C57BL/6 mice expressing the enhanced green fluorescent protein (EGFP) transgene were transplanted into syngeneic wild-type recipients. Motile activities of EGFP(+) corneal LCs in intact organ cultures were then recorded by time lapse two-photon microscopy. At baseline, corneal LCs exhibited a unique motion, termed dendrite surveillance extension and retraction cycling habitude (dSEARCH), characterized by rhythmic extension and retraction of their dendritic processes through intercellular spaces between epithelial cells. Upon pinpoint injury produced by infrared laser, LCs showed augmented dSEARCH and amoeba-like lateral movement. Interleukin (IL)-1 receptor antagonist completely abrogated both injury-associated changes, suggesting roles for IL-1. In the absence of injury, exogenous IL-1 caused a transient increase in dSEARCH without provoking lateral migration, whereas tumour necrosis factor-alpha induced both changes. Our results demonstrate rapid cytokine-mediated behavioural responses by LCs to local tissue injury, providing new insights into the biology of LCs.


Assuntos
Lesões da Córnea , Queimaduras Oculares/imunologia , Células de Langerhans/imunologia , Animais , Transplante de Medula Óssea , Comunicação Celular/imunologia , Córnea/imunologia , Células Dendríticas/imunologia , Epitélio Corneano/imunologia , Interleucina-1/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microscopia Confocal , Técnicas de Cultura de Órgãos , Fator de Necrose Tumoral alfa/imunologia
11.
J Invest Dermatol ; 126(11): 2452-7, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16794586

RESUMO

Although several studies have suggested relatively slow turnover of Langerhans cells (LCs), their actual lifespan remains elusive. Here we report the development of a new intravital imaging system for studying LC efflux and influx. Epidermal LCs expressing enhanced green fluorescent protein (EGFP) were visualized in anesthetized I-Abeta-EGFP knock-in mice by confocal microscopy. By overlaying two sets of EGFP+ LC images recorded in the same microscopic fields at time 0 and 24 hours later, we identified LC subpopulations that had disappeared from or newly emerged in the epidermis during that period. Of >10,000 LCs analyzed in this manner, an overwhelming majority (97.8+/-0.2%) of LCs showed no significant changes in the x-y locations, whereas 1.3+/-0.1% of the LCs that were found at time 0 became undetectable 24 hours later, representing LC efflux. Conversely, 0.9+/-0.1% of the LCs that were found at time 24 hours were not detectable at time 0, representing LC influx. From these frequencies, we estimated the half-life of epidermal LCs to range from 53 to 78 days, providing new insights into the immunobiology of LCs. Our intermittent imaging approach may be regarded as a technical breakthrough enabling direct visual assessment of LC turnover in living animals.


Assuntos
Células Epidérmicas , Proteínas de Fluorescência Verde/análise , Células de Langerhans/citologia , Microscopia Confocal/métodos , Animais , Proteínas de Fluorescência Verde/genética , Células de Langerhans/química , Camundongos , Camundongos Mutantes
12.
Blood ; 102(5): 1654-60, 2003 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-12738661

RESUMO

Several leukocyte populations normally reside in mouse skin, including Langerhans cells and gammadelta T cells in the epidermis and macrophage and mast cells in the dermis. Interestingly, these skin resident leukocytes are frequently identified within or around hair follicles (HFs), which are known to contain stem cell populations that can generate the epidermal architecture or give rise to the melanocyte lineage. Thus, we reasoned that HFs might serve as a local reservoir of the resident leukocyte populations in the skin. When vibrissal follicles of adult mice were cultured in the presence of stem cell factor (SCF), interleukin 3 (IL-3), IL-7, granulocyte-macrophage colony-stimulating factor, and Flt3 ligand, CD45+/lineage-/c-kit+/FcepsilonRI+ cells became detectable on the outgrowing fibroblasts in 10 days and expanded progressively thereafter. These HF-derived leukocytes showed characteristic features of connective tissue-type mast cells, including proliferative responsiveness to SCF, metachromatic granules, mRNA expression for mast cell proteases-1, -4, -5, and -6, and histamine release on ligation of surface IgE or stimulation with substance P or compound 48/80. These results, together with our findings that HFs contain c-kit+ cells and produce SCF mRNA and protein, suggest that HFs provide a unique microenvironment for local development of mast cells.


Assuntos
Folículo Piloso/citologia , Mastócitos/citologia , Células-Tronco/citologia , Animais , Técnicas de Cultura de Células/métodos , Divisão Celular/efeitos dos fármacos , Linhagem da Célula , Células Cultivadas , Meios de Cultura/farmacologia , Imunofenotipagem , Antígenos Comuns de Leucócito/análise , Mastócitos/química , Camundongos , Camundongos Endogâmicos C57BL , Vibrissas/citologia
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