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1.
J Exp Med ; 217(2)2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-31841125

RESUMO

Antibody-mediated autoimmune diseases are a major health burden. However, our understanding of how self-reactive B cells escape self-tolerance checkpoints to secrete pathogenic autoantibodies remains incomplete. Here, we demonstrate that patients with monogenic immune dysregulation caused by gain-of-function mutations in PIK3CD, encoding the p110δ catalytic subunit of phosphoinositide 3-kinase (PI3K), have highly penetrant secretion of autoreactive IgM antibodies. In mice with the corresponding heterozygous Pik3cd activating mutation, self-reactive B cells exhibit a cell-autonomous subversion of their response to self-antigen: instead of becoming tolerized and repressed from secreting autoantibody, Pik3cd gain-of-function B cells are activated by self-antigen to form plasmablasts that secrete high titers of germline-encoded IgM autoantibody and hypermutating germinal center B cells. However, within the germinal center, peripheral tolerance was still enforced, and there was selection against B cells with high affinity for self-antigen. These data show that the strength of PI3K signaling is a key regulator of pregerminal center B cell self-tolerance and thus represents a druggable pathway to treat antibody-mediated autoimmunity.

2.
Biochemistry ; 59(4): 541-551, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-31841311

RESUMO

Blocking interactions between PD-1 and PD-L1 opens a new era of cancer treatment involving immunity modulation. Although most immunotherapies use monoclonal antibodies, small-molecule inhibitors offer advantages. To facilitate development of small-molecule therapeutics, we implemented a rapid approach to characterize the binding interfaces of small-molecule inhibitors with PD-L1. We determined its interaction with a synthetic macrocyclic peptide by using two mass spectrometry-based approaches, hydrogen-deuterium exchange and fast photochemical oxidation of proteins (FPOP), and corroborated the findings with our X-ray structure of the PD-L1/macrocycle complex. Although all three approaches show that the macrocycle binds directly to PD-L1 over the regions of residues 46-87 and 114-125, the two protein footprinting approaches show additional binding at the N-terminus of PD-L1, and FPOP reveals some critical binding residues. The outcomes not only show the binding regions but also demonstrate the utility of MS-based footprinting in probing protein/ligand inhibitory interactions in cancer immunotherapy.

3.
Nat Immunol ; 20(10): 1299-1310, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31534238

RESUMO

Resisting and tolerating microbes are alternative strategies to survive infection, but little is known about the evolutionary mechanisms controlling this balance. Here genomic analyses of anatomically modern humans, extinct Denisovan hominins and mice revealed a TNFAIP3 allelic series with alterations in the encoded immune response inhibitor A20. Each TNFAIP3 allele encoded substitutions at non-catalytic residues of the ubiquitin protease OTU domain that diminished IκB kinase-dependent phosphorylation and activation of A20. Two TNFAIP3 alleles encoding A20 proteins with partial phosphorylation deficits seemed to be beneficial by increasing immunity without causing spontaneous inflammatory disease: A20 T108A;I207L, originating in Denisovans and introgressed in modern humans throughout Oceania, and A20 I325N, from an N-ethyl-N-nitrosourea (ENU)-mutagenized mouse strain. By contrast, a rare human TNFAIP3 allele encoding an A20 protein with 95% loss of phosphorylation, C243Y, caused spontaneous inflammatory disease in humans and mice. Analysis of the partial-phosphorylation A20 I325N allele in mice revealed diminished tolerance of bacterial lipopolysaccharide and poxvirus inoculation as tradeoffs for enhanced immunity.

4.
Nat Med ; 25(9): 1377-1384, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31501601

RESUMO

People living with HIV (PLWH) have expressed concern about the life-long burden and stigma associated with taking pills daily and can experience medication fatigue that might lead to suboptimal treatment adherence and the emergence of drug-resistant viral variants, thereby limiting future treatment options1-3. As such, there is strong interest in long-acting antiretroviral (ARV) agents that can be administered less frequently4. Herein, we report GS-CA1, a new archetypal small-molecule HIV capsid inhibitor with exceptional potency against HIV-2 and all major HIV-1 types, including viral variants resistant to the ARVs currently in clinical use. Mechanism-of-action studies indicate that GS-CA1 binds directly to the HIV-1 capsid and interferes with capsid-mediated nuclear import of viral DNA, HIV particle production and ordered capsid assembly. GS-CA1 selects in vitro for unfit GS-CA1-resistant capsid variants that remain fully susceptible to other classes of ARVs. Its high metabolic stability and low solubility enabled sustained drug release in mice following a single subcutaneous dosing. GS-CA1 showed high antiviral efficacy as a long-acting injectable monotherapy in a humanized mouse model of HIV-1 infection, outperforming long-acting rilpivirine. Collectively, these results demonstrate the potential of ultrapotent capsid inhibitors as new long-acting agents for the treatment of HIV-1 infection.


Assuntos
Fármacos Anti-HIV/farmacologia , Proteínas do Capsídeo/antagonistas & inibidores , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Indazóis/farmacologia , Piridinas/farmacologia , Bibliotecas de Moléculas Pequenas/farmacologia , Animais , Fármacos Anti-HIV/uso terapêutico , Capsídeo/efeitos dos fármacos , Capsídeo/metabolismo , Proteínas do Capsídeo/genética , DNA Viral/efeitos dos fármacos , Preparações de Ação Retardada , Farmacorresistência Viral/efeitos dos fármacos , Infecções por HIV/genética , Infecções por HIV/virologia , HIV-1/genética , HIV-1/patogenicidade , HIV-2/efeitos dos fármacos , HIV-2/patogenicidade , Humanos , Indazóis/uso terapêutico , Adesão à Medicação , Camundongos , Piridinas/uso terapêutico
6.
Front Immunol ; 10: 1544, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31396201

RESUMO

One of the primary targets of immune checkpoint inhibition is the negative immune regulatory molecule CTLA-4. Immune-related adverse events are commonly observed following CTLA-4 inhibition in melanoma treatment, and a spectrum of these conditions are also observed in individuals with germline haploinsufficiency of CTLA4. Here we describe a heterozygous de novo missense variant of CTLA4 in a young girl with childhood-onset autoimmune hepatitis and polyarthritis, the latter responding to treatment with CTLA-4-Ig fusion protein. This variant lay within the highly conserved MYPPPY motif of CTLA-4: a critical structural determinant of ligand binding, which is also bound by the anti-CTLA-4 monoclonal antibody ipilimumab. Within the spectrum of CTLA4 variants reported, missense variants in the MYPPPY motif were overrepresented when compared to variants within a control population, highlighting the physiological importance of this motif in both the genetic and pharmacological regulation of autoimmunity and anti-tumor immunity.

8.
Vaccine ; 37(27): 3562-3567, 2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31128875

RESUMO

Immune responses to the capsular polysaccharide administered in the polysaccharide-protein conjugate vaccines can be either improved or suppressed by the pre-existence of immunity to the carrier protein. Receiving multiple vaccinations is essential for travellers such as Hajj pilgrims, and the use of conjugated vaccines is recommended. We studied the immune response to meningococcal serogroup W upon prior, concurrent and sequential administration of a quadrivalent meningococcal conjugate vaccine (MCV4) conjugated to CRM197 (coadministered with 13 valent pneumococcal vaccine conjugate CRM197 [PCV13]), and tetanus-diphtheria-acellular pertussis (Tdap) vaccine in Australian adults before attending the Hajj pilgrimage in 2014. Participants were randomly assigned, by computer-generated numbers, to three study arms by 1:1:1 ratio. Group A received Tdap followed by MCV4-CRM197 (+PCV13) 3-4 weeks later. Group B received all three vaccines in a single visit. Group C received MCV4-CRM197 (+PCV13) followed by Tdap 3-4 weeks later. Blood samples obtained prior to and 3-4 weeks after immunisation with MCV4-CRM197 were tested for meningococcal serogroup W-specific serum bactericidal antibody responses using baby rabbit complement (rSBA). One hundred and seven participants aged between 18 and 64 (median 40) years completed the study. No significant difference in meningococcal serogroup W rSBA geometric mean titre (GMT) was observed between the study arms post vaccination with MCV-CRM197 but Group A tended to have a slightly lower GMT (A = 404, B = 984 and C = 1235, p = 0.15). No statistical difference was noticed between the groups in proportions of subjects achieving a ≥4-fold rise in rSBA titres or achieving rSBA titre ≥8 post vaccination. In conclusion, receipt of MCV4-CRM197 vaccine prior, concurrent or subsequent to Tdap has similar immunologic response, and hence concurrent administration is both immunogenic and practical. However, further investigation into whether carrier induced suppression is a public health issue is suggested. Clinical trial registration: ANZCTR no. ACTRN12613000536763.

9.
JCI Insight ; 52019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31021819

RESUMO

Bi-allelic inactivating mutations in DOCK8 cause a combined immunodeficiency characterised by severe pathogen infections, eczema, allergies, malignancy and impaired humoral responses. These clinical features result from functional defects in most lymphocyte lineages. Thus, DOCK8 plays a key role in immune cell function. Hematopoietic stem cell transplantation (HSCT) is curative for DOCK8 deficiency. While previous reports have described clinical outcomes for DOCK8 deficiency following HSCT, the effect on lymphocyte reconstitution and function has not been investigated. Our study determined whether defects in lymphocyte differentiation and function in DOCK8-deficient patients were restored following HSCT. DOCK8-deficient T and B lymphocytes exhibited aberrant activation and effector function in vivo and in vitro. Frequencies of αß T and MAIT cells were reduced while γδT cells were increased in DOCK8-deficient patients. HSCT improved, abnormal lymphocyte function in DOCK8-deficient patients. Elevated total and allergen-specific IgE in DOCK8-deficient patients decreased over time following HSCT. Our results document the extensive catalogue of cellular defects in DOCK8-deficient patients, and the efficacy of HSCT to correct these defects, concurrent with improvements in clinical phenotypes. Overall, our findings provide mechanisms at a functional cellular level for improvements in clinical features of DOCK8 deficiency post-HSCT, identify biomarkers that correlate with improved clinical outcomes, and inform the general dynamics of immune reconstitution in patients with monogenic immune disorders following HSCT.

10.
J Allergy Clin Immunol ; 144(1): 236-253, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30738173

RESUMO

BACKGROUND: Gain-of-function (GOF) mutations in PIK3CD cause a primary immunodeficiency characterized by recurrent respiratory tract infections, susceptibility to herpesvirus infections, and impaired antibody responses. Previous work revealed defects in CD8+ T and B cells that contribute to this clinical phenotype, but less is understood about the role of CD4+ T cells in disease pathogenesis. OBJECTIVE: We sought to dissect the effects of increased phosphoinositide 3-kinase (PI3K) signaling on CD4+ T-cell function. METHODS: We performed detailed ex vivo, in vivo, and in vitro phenotypic and functional analyses of patients' CD4+ T cells and a novel murine disease model caused by overactive PI3K signaling. RESULTS: PI3K overactivation caused substantial increases in numbers of memory and follicular helper T (TFH) cells and dramatic changes in cytokine production in both patients and mice. Furthermore, PIK3CD GOF human TFH cells had dysregulated phenotype and function characterized by increased programmed cell death protein 1, CXCR3, and IFN-γ expression, the phenotype of a TFH cell subset with impaired B-helper function. This was confirmed in vivo in which Pik3cd GOF CD4+ T cells also acquired an aberrant TFH phenotype and provided poor help to support germinal center reactions and humoral immune responses by antigen-specific wild-type B cells. The increase in numbers of both memory and TFH cells was largely CD4+ T-cell extrinsic, whereas changes in cytokine production and TFH cell function were cell intrinsic. CONCLUSION: Our studies reveal that CD4+ T cells with overactive PI3K have aberrant activation and differentiation, thereby providing mechanistic insight into dysfunctional antibody responses in patients with PIK3CD GOF mutations.

11.
J Mol Biol ; 431(7): 1440-1459, 2019 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-30753871

RESUMO

Calcium/calmodulin-dependent protein kinase II (CaMKII) is a multifunctional serine/threonine protein kinase that transmits calcium signals in various cellular processes. CaMKII is activated by calcium-bound calmodulin (Ca2+/CaM) through a direct binding mechanism involving a regulatory C-terminal α-helix in CaMKII. The Ca2+/CaM binding triggers transphosphorylation of critical threonine residues proximal to the CaM-binding site leading to the autoactivated state of CaMKII. The demonstration of its critical roles in pathophysiological processes has elevated CaMKII to a key target in the management of numerous diseases. The molecule KN-93 is the most widely used inhibitor for studying the cellular and in vivo functions of CaMKII. It is widely believed that KN-93 binds directly to CaMKII, thus preventing kinase activation by competing with Ca2+/CaM. Herein, we employed surface plasmon resonance, NMR, and isothermal titration calorimetry to characterize this presumed interaction. Our results revealed that KN-93 binds directly to Ca2+/CaM and not to CaMKII. This binding would disrupt the ability of Ca2+/CaM to interact with CaMKII, effectively inhibiting CaMKII activation. Our findings also indicated that KN-93 can specifically compete with a CaMKIIδ-derived peptide for binding to Ca2+/CaM. As indicated by the surface plasmon resonance and isothermal titration calorimetry data, apparently at least two KN-93 molecules can bind to Ca2+/CaM. Our findings provide new insight into how in vitro and in vivo data obtained with KN-93 should be interpreted. They further suggest that other Ca2+/CaM-dependent, non-CaMKII activities should be considered in KN-93-based mechanism-of-action studies and drug discovery efforts.

13.
Epilepsy Behav ; 92: 206-212, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30684800

RESUMO

OBJECTIVES: Psychogenic nonepileptic seizures (PNES) resemble seizures but are psychological in origin. The etiology of PNES remains poorly understood, yet several theories argue for the importance of autonomic dysregulation in its pathophysiology. We therefore conducted a retrospective study to investigate autonomic dynamics leading up to a seizure to inform their mechanistic relevance. METHODS: One hundred one patients with PNES and 45 patients with epileptic seizure (ES) were analyzed for preictal heart rate (HR) and respiratory rate (RR) at baseline and at minute intervals from 5 min to onset. RESULTS: Patients with PNES showed rising HR (p < 0.001, repeated-measures analysis of variance (ANOVA)) and rising RR (p = 0.012, repeated-measures ANOVA) from baseline to the onset of their seizures. Patients with ES did not exhibit significant preictal HR or RR increase. Patients with PNES had nonsignificantly higher preictal HR and RR than patients with ES. SIGNIFICANCE: Patients with PNES exhibit increasing autonomic arousal prior to seizure events unlike patients with epilepsy. This may reflect increasing levels of preictal anxiety, and future studies could study patients' subjective experiences of the preictal period, and more definitive measures of ventilation to see if this supported a model of PNES as "panic without panic".

14.
Sleep Breath ; 23(1): 95-101, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29744684

RESUMO

OBJECTIVES: We explored relationships between biochemical markers and cardiac responses of children with and without obstructive sleep apnoea (OSA) during exercise. We hypothesised that serum markers of sympathetic nervous system activity and low-grade inflammation would correlate with cardiac responses to exercise in children with or without OSA. METHODOLOGY: The study included 40 of 71 children with previously characterised responses to cardiopulmonary exercise testing. Measures included serum cytokine levels using a multiplex bead-based assay (interleukins IL-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, TNF-α and IFN-γ). Serum amyloid A (SAA) was quantified by nephelometry, and metanephrine/normetanephrine levels were measured by liquid chromatography, mass-spectroscopy. Comparisons were made between children with and without OSA, and with and without obesity. Relationships between biomarkers and various cardiac parameters were explored by linear regression. RESULTS: Amongst the 40 children in this study, OSA was present in 23. Compared to the 17 children without OSA, those with OSA had higher resting serum IL-6 levels compared to those without (median 3.22 pg/ml vs. 2.31, p < 0.05). Regarding correlations with cardiac function after adjusting for OSA, IL-8 negatively correlated to heart rate (HR) response following exercise (p = 0.03) and IFN-γ negatively correlated with Stroke Volume Index (SVI) (p = 0.03). Both metanephrine and normetanephrine levels positively correlated with SVI (p = 0.04, p = 0.047; respectively) and QI (p = 0.04, p = 0.04; respectively) during exercise when adjusting for OSA. CONCLUSIONS: Children with OSA have raised morning levels of serum IL-6. Separately, higher levels of IFN-γ and IL-8 and lower levels of metanephrine and normetanephrine related to poorer cardiac function during exercise.


Assuntos
Arritmias Cardíacas/imunologia , Arritmias Cardíacas/fisiopatologia , Citocinas/sangue , Apneia Obstrutiva do Sono/imunologia , Biomarcadores/sangue , Criança , Estudos Transversais , Exercício/fisiologia , Feminino , Humanos , Masculino , Índice de Gravidade de Doença , Apneia Obstrutiva do Sono/sangue
15.
J Allergy Clin Immunol ; 143(1): 276-291.e6, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29800648

RESUMO

BACKGROUND: Germline gain-of function (GOF) mutations in PIK3CD, encoding the catalytic p110δ subunit of phosphoinositide 3-kinase (PI3K), result in hyperactivation of the PI3K-AKT-mechanistic target of rapamycin pathway and underlie a novel inborn error of immunity. Affected subjects exhibit perturbed humoral and cellular immunity, manifesting as recurrent infections, autoimmunity, hepatosplenomegaly, uncontrolled EBV and/or cytomegalovirus infection, and increased incidence of B-cell lymphoproliferation, lymphoma, or both. Mechanisms underlying disease pathogenesis remain unknown. OBJECTIVE: Understanding the cellular and molecular mechanisms underpinning inefficient surveillance of EBV-infected B cells is required to understand disease in patients with PIK3CD GOF mutations, identify key molecules required for cell-mediated immunity against EBV, and develop immunotherapeutic interventions for the treatment of this and other EBV-opathies. METHODS: We studied the consequences of PIK3CD GOF mutations on the generation, differentiation, and function of CD8+ T cells and natural killer (NK) cells, which are implicated in host defense against infection with herpesviruses, including EBV. RESULTS: PIK3CD GOF total and EBV-specific CD8+ T cells were skewed toward an effector phenotype, with exaggerated expression of markers associated with premature immunosenescence/exhaustion and increased susceptibility to reactivation-induced cell death. These findings were recapitulated in a novel mouse model of PI3K GOF mutations. NK cells in patients with PIK3CD GOF mutations also exhibited perturbed expression of differentiation-associated molecules. Both CD8+ T and NK cells had reduced capacity to kill EBV-infected B cells. PIK3CD GOF B cells had increased expression of CD48, programmed death ligand 1/2, and CD70. CONCLUSIONS: PIK3CD GOF mutations aberrantly induce exhaustion, senescence, or both and impair cytotoxicity of CD8+ T and NK cells. These defects might contribute to clinical features of affected subjects, such as impaired immunity to herpesviruses and tumor surveillance.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Diferenciação Celular/imunologia , Classe I de Fosfatidilinositol 3-Quinases , Infecções por Vírus Epstein-Barr , Mutação com Ganho de Função , Doenças Genéticas Inatas/imunologia , Herpesvirus Humano 4/imunologia , Células Matadoras Naturais/imunologia , Adolescente , Adulto , Idoso , Linfócitos B/imunologia , Linfócitos T CD8-Positivos/patologia , Diferenciação Celular/genética , Senescência Celular/genética , Senescência Celular/imunologia , Criança , Pré-Escolar , Classe I de Fosfatidilinositol 3-Quinases/genética , Classe I de Fosfatidilinositol 3-Quinases/imunologia , Infecções por Vírus Epstein-Barr/genética , Infecções por Vírus Epstein-Barr/imunologia , Infecções por Vírus Epstein-Barr/patologia , Doenças Genéticas Inatas/genética , Doenças Genéticas Inatas/patologia , Humanos , Vigilância Imunológica/genética , Células Matadoras Naturais/patologia , Masculino , Pessoa de Meia-Idade
16.
J Clin Invest ; 128(10): 4485-4500, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30024858

RESUMO

Oxidative stress is an underlying component of acute and chronic kidney disease. Apoptosis signal-regulating kinase 1 (ASK1) is a widely expressed redox-sensitive serine threonine kinase that activates p38 and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase kinases, and induces apoptotic, inflammatory, and fibrotic signaling in settings of oxidative stress. We describe the discovery and characterization of a potent and selective small-molecule inhibitor of ASK1, GS-444217, and demonstrate the therapeutic potential of ASK1 inhibition to reduce kidney injury and fibrosis. Activation of the ASK1 pathway in glomerular and tubular compartments was confirmed in renal biopsies from patients with diabetic kidney disease (DKD) and was decreased by GS-444217 in several rodent models of kidney injury and fibrosis that collectively represented the hallmarks of DKD pathology. Treatment with GS-444217 reduced progressive inflammation and fibrosis in the kidney and halted glomerular filtration rate decline. Combination of GS-444217 with enalapril, an angiotensin-converting enzyme inhibitor, led to a greater reduction in proteinuria and regression of glomerulosclerosis. These results identify ASK1 as an important target for renal disease and support the clinical development of an ASK1 inhibitor for the treatment of DKD.


Assuntos
Nefropatias Diabéticas/enzimologia , Fibroblastos/enzimologia , Glomérulos Renais/enzimologia , MAP Quinase Quinase Quinase 5/metabolismo , Sistema de Sinalização das MAP Quinases , Animais , Nefropatias Diabéticas/tratamento farmacológico , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/patologia , Modelos Animais de Doenças , Feminino , Fibroblastos/patologia , Fibrose , Humanos , Glomérulos Renais/patologia , MAP Quinase Quinase Quinase 5/antagonistas & inibidores , MAP Quinase Quinase Quinase 5/genética , Masculino , Camundongos , Camundongos Knockout , Inibidores de Proteínas Quinases/farmacologia , Distribuição Aleatória , Ratos Sprague-Dawley
17.
Front Immunol ; 9: 1535, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30038614

RESUMO

Background: Mutations in the gene encoding stimulator of interferon genes (STING) underlie a type I interferon (IFN) associated disease, STING-associated vasculopathy with onset in infancy (SAVI). Patients suffer cutaneous vasculopathy and interstitial lung disease, but are not known to suffer life-threatening infection. Case: We describe a child who presented with Pneumocystis jirovecii pneumonia in early life, from which he recovered. He went on to suffer failure to thrive, developmental delay, livedo reticularis, and vesicular rash, but without cutaneous vasculitis, and with normal C-reactive protein and erythrocyte sedimentation rates. At 3 years of age, he developed life-threatening pulmonary hypertension. Methods: Whole genome sequencing (WGS) was performed using the Illumina HiSeqX10 platform and the Seave platform was used for bioinformatic analysis. mRNA expression of IFN-stimulated genes and inflammatory cytokines from peripheral blood mononuclear cells was determined by quantitative polymerase chain reaction. Luciferase assay was used to model IFNß and NF-κB activity in vitro. Results: WGS revealed a de novo mutation p.Arg284Ser in STING at an amino acid previously associated with SAVI. Although this mutation did not fall in the dimerization domain (DD), mRNA analysis revealed constitutive IFN-gene activation consistent with an interferonopathy, which correlated to STING activation in vitro. The patient was treated with corticosteroids and the JAK inhibitor Ruxolitinib, resulting in a rapid improvement of pulmonary hypertension, general well-being, and resolution of the IFN gene signature. However, he did go on to evolve a nasal septal erosion suggesting incomplete control of disease. Conclusion: This case provides molecular evidence to support the p.Arg284Ser variant in STING exerting pathogenicity through a gain-of-function mechanism. The lack of cutaneous vasculitis or elevated systemic inflammatory markers, and the occurrence of an opportunistic infection are notable, and raise the possibility that variants outside the STING DD may potentially manifest with an atypical SAVI phenotype. Nevertheless, there was an objective clinical improvement in response to JAK inhibition.

18.
J Exp Med ; 215(8): 2073-2095, 2018 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-30018075

RESUMO

Gain-of-function (GOF) mutations in PIK3CD, encoding the p110δ subunit of phosphatidylinositide 3-kinase (PI3K), cause a primary immunodeficiency. Affected individuals display impaired humoral immune responses following infection or immunization. To establish mechanisms underlying these immune defects, we studied a large cohort of patients with PIK3CD GOF mutations and established a novel mouse model using CRISPR/Cas9-mediated gene editing to introduce a common pathogenic mutation in Pik3cd In both species, hyperactive PI3K severely affected B cell development and differentiation in the bone marrow and the periphery. Furthermore, PI3K GOF B cells exhibited intrinsic defects in class-switch recombination (CSR) due to impaired induction of activation-induced cytidine deaminase (AID) and failure to acquire a plasmablast gene signature and phenotype. Importantly, defects in CSR, AID expression, and Ig secretion were restored by leniolisib, a specific p110δ inhibitor. Our findings reveal key roles for balanced PI3K signaling in B cell development and long-lived humoral immunity and memory and establish the validity of treating affected individuals with p110δ inhibitors.


Assuntos
Linfócitos B/citologia , Linfócitos B/imunologia , Classe I de Fosfatidilinositol 3-Quinases/genética , Mutação em Linhagem Germinativa/genética , Fosfatidilinositol 3-Quinases/genética , Animais , Afinidade de Anticorpos/imunologia , Células da Medula Óssea/citologia , Diferenciação Celular , Proliferação de Células , Criança , Mutação com Ganho de Função/genética , Humanos , Switching de Imunoglobulina , Imunoglobulinas/metabolismo , Interleucinas/farmacologia , Camundongos , Modelos Animais , Fenótipo , Fosfatidilinositol 3-Quinases/metabolismo , Plasmócitos/metabolismo , Transdução de Sinais
19.
J Paediatr Child Health ; 54(11): 1255-1261, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29889338

RESUMO

AIM: Pompe disease is a rare, autosomal, recessive disorder. Alterations in the gene encoding lysosomal acid alpha-glucosidase cause impaired glycogen degradation and resultant lysosomal glycogen accumulation. Classic infantile-onset Pompe disease (IPD) manifests soon after birth, severe cases have complete/near complete enzyme deficiency. IPD is associated with a broad spectrum of non-specific clinical features, and diagnostic delays are common. Without treatment, death typically occurs within the first 2 years of life. We present case experiences to help expand paediatricians' understanding of factors contributing to diagnostic delay, clinical decline and to highlight the need for timely therapy. METHODS: Data were extracted from IPD cases managed at our hospital. Key aspects of clinical presentation, diagnosis, genetic variations, management and overall outcomes were collated then compared with what is already known in the literature. RESULTS: We report four IPD cases (three female). Two patients were cross-reactive immunological material negative. Age at symptom onset was 3-9 months, presenting clinical features were varied, and confirmatory diagnosis was significantly delayed in one patient. In concert with the literature, cardiomegaly, ventricular hypertrophy and delayed developmental milestones were seen in all four cases. Our cases demonstrate a range of disease severity, response to enzyme replacement therapy and antibody development. Significant immune responses were seen in two cases (one cross-reactive immunological material positive); despite immunomodulation therapy, both were associated with fatal outcomes. CONCLUSION: Timely diagnosis and initiation of enzyme replacement therapy is critical to patient outcomes as IPD progresses rapidly and irreversible changes in clinical status may occur during the delay.

20.
J Immunol ; 200(12): 3970-3980, 2018 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-29720424

RESUMO

Recent evidence suggests early environmental factors are important for gut immune tolerance. Although the role of regulatory T (Treg) cells for gut immune homeostasis is well established, the development and tissue homing characteristics of Treg cells in children have not been studied in detail. In this article, we studied the development and homing characteristics of human peripheral blood Treg cell subsets and potential mechanisms inducing homing molecule expression in healthy children. We found contrasting patterns of circulating Treg cell gut and skin tropism, with abundant ß7 integrin+ Treg cells at birth and increasing cutaneous lymphocyte Ag (CLA+) Treg cells later in life. ß7 integrin+ Treg cells were predominantly naive, suggesting acquisition of Treg cell gut tropism early in development. In vitro, IL-7 enhanced gut homing but reduced skin homing molecule expression in conventional T cells, whereas IL-2 induced a similar effect only in Treg cells. This effect was more pronounced in cord compared with adult blood. Our results suggest that early in life, naive Treg cells may be driven for gut tropism by their increased sensitivity to IL-2-induced ß7 integrin upregulation, implicating a potential role of IL-2 in gut immune tolerance during this critical period of development.


Assuntos
Trato Gastrointestinal/imunologia , Interleucina-2/imunologia , Receptores de Retorno de Linfócitos/imunologia , Linfócitos T Reguladores/imunologia , Adolescente , Antígenos/imunologia , Células Cultivadas , Criança , Pré-Escolar , Feminino , Humanos , Tolerância Imunológica/imunologia , Lactente , Recém-Nascido , Cadeias beta de Integrinas/imunologia , Interleucina-7/imunologia , Masculino , Pele/imunologia , Tropismo/imunologia , Regulação para Cima/imunologia
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