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1.
Stud Health Technol Inform ; 310: 159-163, 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38269785

RESUMEN

Systemic Lupus Erythematosus (SLE) is a widespread autoimmune disease for which early diagnosis is paramount in improving clinical outcomes. In this project, we used the de-identified patients from Epic Cosmos to retrieve the ICD code for SLE, checked data quality based on the EULAR/ACR classification systems, created an approach to determine the SLE patients, and performed statistical analyses on lab tests and clinical characteristics. Our preliminary results showed that clinical notes must be reviewed to improve the completeness, as structured EHR data fields provide limited information in determining if a patient meets the established classification criteria.


Asunto(s)
Lupus Eritematoso Sistémico , Humanos , Lupus Eritematoso Sistémico/diagnóstico , Exactitud de los Datos , Clasificación Internacional de Enfermedades , Pacientes , Fenotipo
2.
Clin Immunol ; 255: 109763, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37673226

RESUMEN

To explore the antibody response to Z-DNA, a DNA conformation with a zig-zag structure, blood of patients with systemic lupus erythematosus (SLE) and otherwise healthy individuals (NHS) were assayed by ELISA using brominated poly(dGdC), a synthetic Z-DNA antigen. These studies showed that SLE patients commonly express antibodies to Z-DNA; NHS also had binding in this assay. In SLE blood, levels of antibodies to Z-DNA were related to those to B-DNA using calf thymus DNA as a source of B-DNA; cross-reactivity was demonstrated by adsorption experiments using DNA cellulose. As shown by dissociation assays, antibody binding of SLE anti-Z-DNA is sensitive to the effects of ionic strength, suggesting electrostatic binding. Since Z-DNA structure can be found in bacterial DNA as well as bacterial biofilms, these findings suggest that, in SLE, anti-DNA antibody responses can result from stimulation by DNA of bacterial origin, with cross-reactivity leading to autoreactivity.

4.
EBioMedicine ; 85: 104299, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36209522

RESUMEN

A hyperinflammatory response during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection crucially worsens clinical evolution of coronavirus disease 2019 (COVID-19). The interaction between SARS-CoV-2 and angiotensin-converting enzyme 2 (ACE2) triggers the activation of the NACHT, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome. Enhanced inflammasome activity has been associated with increased disease severity and poor prognosis. Evidence suggests that inflammasome activation and interleukin-1ß (IL-1ß) release aggravate pulmonary injury and induce hypercoagulability, favoring progression to respiratory failure and widespread thrombosis eventually leading to multiorgan failure and death. Observational studies with the IL-1 blockers anakinra and canakinumab provided promising results. In the SAVE-MORE trial, early treatment with anakinra significantly shortened hospital stay and improved survival in patients with moderate-to-severe COVID-19. In this review, we summarize current evidence supporting the pathogenetic role of the NLRP3 inflammasome and IL-1ß in COVID-19, and discuss clinical trials testing IL-1 inhibition in COVID-19.


Asunto(s)
Tratamiento Farmacológico de COVID-19 , COVID-19 , Inflamasomas , Humanos , Inflamasomas/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , COVID-19/complicaciones , Proteína Antagonista del Receptor de Interleucina 1 , SARS-CoV-2 , Interleucina-1beta/metabolismo
5.
Minerva Med ; 113(6): 1000-1007, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34269550

RESUMEN

The ongoing coronavirus disease 2019 (COVID-19) pandemic has placed tremendous strain on health systems throughout the world. This has led to many clinical trials being launched in order to try to find ways to combat the disease. The unprecedented nature of the pandemic has been reflected in the methods used in some of these trials. Placebo-controlled randomized trials are considered the gold-standard, however, there are inherent challenges in the use of placebo, especially during COVID-19. We herein review the pros, cons, challenges and limitations of using placebo in clinical trials investigating treatments for COVID-19. We also discuss the importance of viewing research critically, examining the potential impact of placebo use or lack thereof, on blinding and possible biases. This becomes important as we assess the responses to the pandemic in preparation for a future pandemic. Although placebo-controlled clinical trials are the gold standard for clinical research, they may not be practically or ethically feasible during a pandemic. Choices accomplished to design many COVID-19 trials might reflect the unprecedently trying environment in which they were made. However, critical evaluation of the methodology and practice of scientific research remains a crucial part of the scientific process. Even when conducted as randomized double-blind studies, residual biases may exist and interfere with the study conduct and interpretation of the data. A critical review of all data remains essential to thoroughly assess the impact of a research study.


Asunto(s)
COVID-19 , Humanos , Pandemias , SARS-CoV-2 , Método Doble Ciego , Sesgo , Ensayos Clínicos Controlados Aleatorios como Asunto
6.
J Clin Invest ; 131(24)2021 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-34710063

RESUMEN

Acute COVID-19, caused by SARS-CoV-2, is characterized by diverse clinical presentations, ranging from asymptomatic infection to fatal respiratory failure, and often associated with varied longer-term sequelae. Over the past 18 months, it has become apparent that inappropriate immune responses contribute to the pathogenesis of severe COVID-19. Researchers working at the intersection of COVID-19 and autoimmunity recently gathered at an American Autoimmune Related Diseases Association Noel R. Rose Colloquium to address the current state of knowledge regarding two important questions: Does established autoimmunity predispose to severe COVID-19? And, at the same time, can SARS-CoV-2 infection trigger de novo autoimmunity? Indeed, work to date has demonstrated that 10% to 15% of patients with critical COVID-19 pneumonia exhibit autoantibodies against type I interferons, suggesting that preexisting autoimmunity underlies severe disease in some patients. Other studies have identified functional autoantibodies following infection with SARS-CoV-2, such as those that promote thrombosis or antagonize cytokine signaling. These autoantibodies may arise from a predominantly extrafollicular B cell response that is more prone to generating autoantibody-secreting B cells. This Review highlights the current understanding, evolving concepts, and unanswered questions provided by this unique opportunity to determine mechanisms by which a viral infection can be exacerbated by, and even trigger, autoimmunity. The potential role of autoimmunity in post-acute sequelae of COVID-19 is also discussed.


Asunto(s)
Autoanticuerpos/química , Autoinmunidad/inmunología , COVID-19/inmunología , COVID-19/fisiopatología , Transducción de Señal , Animales , Enfermedades Autoinmunes , Linfocitos B/citología , Citocinas/metabolismo , Progresión de la Enfermedad , Femenino , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Humanos , Inflamación , Interleucina-1/metabolismo , Interleucina-6/metabolismo , Activación de Macrófagos , Masculino , Ratones , Fosfolípidos/metabolismo , SARS-CoV-2
8.
JAMA ; 326(3): 230-239, 2021 07 20.
Artículo en Inglés | MEDLINE | ID: mdl-34283183

RESUMEN

Importance: Effective treatments for patients with severe COVID-19 are needed. Objective: To evaluate the efficacy of canakinumab, an anti-interleukin-1ß antibody, in patients hospitalized with severe COVID-19. Design, Setting, and Participants: This randomized, double-blind, placebo-controlled phase 3 trial was conducted at 39 hospitals in Europe and the United States. A total of 454 hospitalized patients with COVID-19 pneumonia, hypoxia (not requiring invasive mechanical ventilation [IMV]), and systemic hyperinflammation defined by increased blood concentrations of C-reactive protein or ferritin were enrolled between April 30 and August 17, 2020, with the last assessment of the primary end point on September 22, 2020. Intervention: Patients were randomly assigned 1:1 to receive a single intravenous infusion of canakinumab (450 mg for body weight of 40-<60 kg, 600 mg for 60-80 kg, and 750 mg for >80 kg; n = 227) or placebo (n = 227). Main Outcomes and Measures: The primary outcome was survival without IMV from day 3 to day 29. Secondary outcomes were COVID-19-related mortality, measurements of biomarkers of systemic hyperinflammation, and safety evaluations. Results: Among 454 patients who were randomized (median age, 59 years; 187 women [41.2%]), 417 (91.9%) completed day 29 of the trial. Between days 3 and 29, 198 of 223 patients (88.8%) survived without requiring IMV in the canakinumab group and 191 of 223 (85.7%) in the placebo group, with a rate difference of 3.1% (95% CI, -3.1% to 9.3%) and an odds ratio of 1.39 (95% CI, 0.76 to 2.54; P = .29). COVID-19-related mortality occurred in 11 of 223 patients (4.9%) in the canakinumab group vs 16 of 222 (7.2%) in the placebo group, with a rate difference of -2.3% (95% CI, -6.7% to 2.2%) and an odds ratio of 0.67 (95% CI, 0.30 to 1.50). Serious adverse events were observed in 36 of 225 patients (16%) treated with canakinumab vs 46 of 223 (20.6%) who received placebo. Conclusions and Relevance: Among patients hospitalized with severe COVID-19, treatment with canakinumab, compared with placebo, did not significantly increase the likelihood of survival without IMV at day 29. Trial Registration: ClinicalTrials.gov Identifier: NCT04362813.


Asunto(s)
Anticuerpos Monoclonales Humanizados/uso terapéutico , Tratamiento Farmacológico de COVID-19 , Interleucina-1beta/antagonistas & inhibidores , Respiración Artificial/estadística & datos numéricos , Anciano , Anticuerpos Monoclonales Humanizados/efectos adversos , Proteína C-Reactiva/análisis , COVID-19/mortalidad , COVID-19/terapia , Terapia Combinada , Método Doble Ciego , Femenino , Ferritinas/sangre , Productos de Degradación de Fibrina-Fibrinógeno/análisis , Hospitalización , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Tasa de Supervivencia , Resultado del Tratamiento
10.
Front Immunol ; 12: 661437, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33986751

RESUMEN

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of autoantibodies predominantly to nuclear material. Many aspects of disease pathology are mediated by the deposition of nucleic acid containing immune complexes, which also induce the type 1interferon response, a characteristic feature of SLE. Notably, SLE is remarkably heterogeneous, with a variety of organs involved in different individuals, who also show variation in disease severity related to their ancestries. Here, we probed one potential contribution to disease heterogeneity as well as a possible source of immunoreactive nucleic acids by exploring the expression of human endogenous retroviruses (HERVs). We investigated the expression of HERVs in SLE and their potential relationship to SLE features and the expression of biochemical pathways, including the interferon gene signature (IGS). Towards this goal, we analyzed available and new RNA-Seq data from two independent whole blood studies using Telescope. We identified 481 locus specific HERV encoding regions that are differentially expressed between case and control individuals with only 14% overlap of differentially expressed HERVs between these two datasets. We identified significant differences between differentially expressed HERVs and non-differentially expressed HERVs between the two datasets. We also characterized the host differentially expressed genes and tested their association with the differentially expressed HERVs. We found that differentially expressed HERVs were significantly more physically proximal to host differentially expressed genes than non-differentially expressed HERVs. Finally, we capitalized on locus specific resolution of HERV mapping to identify key molecular pathways impacted by differential HERV expression in people with SLE.


Asunto(s)
Retrovirus Endógenos/genética , Perfilación de la Expresión Génica/métodos , Regulación Viral de la Expresión Génica , Interferones/genética , Lupus Eritematoso Sistémico/genética , Adulto , Femenino , Ontología de Genes , Genoma Humano/genética , Genómica/métodos , Humanos , Lupus Eritematoso Sistémico/inmunología , Lupus Eritematoso Sistémico/virología , Masculino , Persona de Mediana Edad , RNA-Seq/métodos , Adulto Joven
11.
Chest ; 159(1): e7-e11, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-32931823

RESUMEN

Coronavirus disease 2019 (COVID-19) has resulted in significant morbidity and mortality because of a lack of effective therapies. Therapeutic strategies under investigation target the overactive cytokine response with anti-cytokine or immunomodulators therapies. We present a unique case of severe cytokine storm resistant to multiple anti-cytokine therapies, but eventually responsive to etoposide. Thus, etoposide may have a role as salvage therapy in treatment of cytokine storm in COVID-19. To our knowledge, this is the first reported case of use of etoposide in COVID-19.


Asunto(s)
COVID-19/complicaciones , Síndrome de Liberación de Citoquinas/tratamiento farmacológico , Síndrome de Liberación de Citoquinas/etiología , Etopósido/uso terapéutico , Anciano , Femenino , Humanos , Terapia Recuperativa/métodos , Índice de Severidad de la Enfermedad
12.
J Vasc Surg Venous Lymphat Disord ; 9(3): 585-591.e2, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-32979557

RESUMEN

BACKGROUND: Infection with the novel severe acute respiratory syndrome coronavirus 2 has been associated with a hypercoagulable state. Emerging data from China and Europe have consistently shown an increased incidence of venous thromboembolism (VTE). We aimed to identify the VTE incidence and early predictors of VTE at our high-volume tertiary care center. METHODS: We performed a retrospective cohort study of 147 patients who had been admitted to Temple University Hospital with coronavirus disease 2019 (COVID-19) from April 1, 2020 to April 27, 2020. We first identified the VTE (pulmonary embolism [PE] and deep vein thrombosis [DVT]) incidence in our cohort. The VTE and no-VTE groups were compared by univariable analysis for demographics, comorbidities, laboratory data, and treatment outcomes. Subsequently, multivariable logistic regression analysis was performed to identify the early predictors of VTE. RESULTS: The 147 patients (20.9% of all admissions) admitted to a designated COVID-19 unit at Temple University Hospital with a high clinical suspicion of acute VTE had undergone testing for VTE using computed tomography pulmonary angiography and/or extremity venous duplex ultrasonography. The overall incidence of VTE was 17% (25 of 147). Of the 25 patients, 16 had had acute PE, 14 had had acute DVT, and 5 had had both PE and DVT. The need for invasive mechanical ventilation (adjusted odds ratio, 3.19; 95% confidence interval, 1.07-9.55) and the admission D-dimer level ≥1500 ng/mL (adjusted odds ratio, 3.55; 95% confidence interval, 1.29-9.78) were independent markers associated with VTE. The all-cause mortality in the VTE group was greater than that in the non-VTE group (48% vs 22%; P = .007). CONCLUSIONS: Our study represents one of the earliest reported from the United States on the incidence rate of VTE in patients with COVID-19. Patients with a high clinical suspicion and the identified risk factors (invasive mechanical ventilation, admission D-dimer level ≥1500 ng/mL) should be considered for early VTE testing. We did not screen all patients admitted for VTE; therefore, the true incidence of VTE could have been underestimated. Our findings require confirmation in future prospective studies.


Asunto(s)
COVID-19 , Productos de Degradación de Fibrina-Fibrinógeno/análisis , Embolia Pulmonar , Respiración Artificial/métodos , Trombosis de la Vena , COVID-19/sangre , COVID-19/complicaciones , COVID-19/epidemiología , Angiografía por Tomografía Computarizada/métodos , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Philadelphia/epidemiología , Pronóstico , Embolia Pulmonar/diagnóstico , Embolia Pulmonar/epidemiología , Embolia Pulmonar/etiología , Estudios Retrospectivos , Factores de Riesgo , SARS-CoV-2 , Trombofilia/sangre , Trombofilia/diagnóstico , Trombofilia/etiología , Ultrasonografía Doppler Dúplex/métodos , Trombosis de la Vena/diagnóstico , Trombosis de la Vena/epidemiología , Trombosis de la Vena/etiología
13.
Ann Rheum Dis ; 80(1): 88-95, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-32978237

RESUMEN

OBJECTIVES: To develop predictive criteria for COVID-19-associated cytokine storm (CS), a severe hyperimmune response that results in organ damage in some patients infected with COVID-19. We hypothesised that criteria for inflammation and cell death would predict this type of CS. METHODS: We analysed 513 hospitalised patients who were positive for COVID-19 reverse transcriptase PCR and for ground-glass opacity by chest high-resolution CT. To achieve an early diagnosis, we analysed the laboratory results of the first 7 days of hospitalisation. We implemented logistic regression and principal component analysis to determine the predictive criteria. We used a 'genetic algorithm' to derive the cut-offs for each laboratory result. We validated the criteria with a second cohort of 258 patients. RESULTS: We found that the criteria for macrophage activation syndrome, haemophagocytic lymphohistiocytosis and the HScore did not identify the COVID-19 cytokine storm (COVID-CS). We developed new predictive criteria, with sensitivity and specificity of 0.85 and 0.80, respectively, comprising three clusters of laboratory results that involve (1) inflammation, (2) cell death and tissue damage, and (3) prerenal electrolyte imbalance. The criteria identified patients with longer hospitalisation and increased mortality. These results highlight the relevance of hyperinflammation and tissue damage in the COVID-CS. CONCLUSIONS: We propose new early predictive criteria to identify the CS occurring in patients with COVID-19. The criteria can be readily used in clinical practice to determine the need for an early therapeutic regimen, block the hyperimmune response and possibly decrease mortality.


Asunto(s)
COVID-19/complicaciones , COVID-19/inmunología , Síndrome de Liberación de Citoquinas/diagnóstico , Síndrome de Liberación de Citoquinas/virología , Anciano , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , SARS-CoV-2 , Sensibilidad y Especificidad
14.
Arthritis Rheumatol ; 72(11): 1872-1881, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32840064

RESUMEN

OBJECTIVE: Infections contribute to morbidity and mortality in systemic lupus erythematosus (SLE). Uropathogenic Escherichia coli (UPEC) are known to trigger urinary tract infections (UTIs) and form biofilms, which are multicellular communities of bacteria that are strengthened by amyloids such as curli. We previously reported that curli naturally form complexes with bacterial extracellular DNA (eDNA), and these curli/eDNA complexes induce hallmark features of lupus in mouse models. The present study was undertaken to investigate whether anti-curli/eDNA complex antibodies play a role in the pathogenesis of SLE or development of flares in SLE. METHODS: In total, 96 SLE patients who met at least 4 Systemic Lupus International Collaborating Clinics disease criteria were investigated. Anti-curli/eDNA complex antibodies in the plasma were tested for both IgG and IgA subclasses. Results were compared to that in 54 age-, sex-, and race/ethnicity-matched healthy controls. Correlations of the levels of anti-curli/eDNA antibodies with clinical parameters, lupus disease status, and frequency of bacteriuria were assessed. RESULTS: Anti-curli/eDNA antibodies were detected in the plasma of SLE patients and healthy controls, and their levels correlated with the presence of asymptomatic persistent bacteriuria and occurrence of disease flares in lupus patients. Persistent bacteriuria contained curli-producing UPEC, and this was associated with an inflammatory phenotype. Finally, curli/eDNA complexes cross-reacted with lupus autoantigens, such as double-stranded DNA, in binding autoantibodies. CONCLUSION: These results suggest that UTIs and persistent bacteriuria are environmental triggers of lupus and its flares. Antibodies against curli/eDNA could serve as a sign of systemic exposure to bacterial products in SLE.


Asunto(s)
Anticuerpos Antinucleares/inmunología , Autoanticuerpos/inmunología , Bacteriuria/inmunología , Escherichia coli/inmunología , Lupus Eritematoso Sistémico/inmunología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven
15.
Cureus ; 12(5): e8130, 2020 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-32550050

RESUMEN

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition caused by overproduction of inflammatory cytokines and overactivation of macrophages that can progress to multiorgan dysfunction and failure. Although there are guidelines that attempt to recognize the condition in its early stage, diagnosis can be very challenging due to heterogeneous presentations of HLH. Symptoms and clinical findings include fever, neurologic complaints, respiratory issues, liver dysfunction, cytopenias, amongst others most of which are not specific to HLH. In addition, response to treatment can be highly variable, necessitating an individualized treatment plan based on the presentation. We present a case of a 21-year-old female with a history of biopsy-proven inflammatory myositis on azathioprine and prednisone who presented with fever, hypotension, and pancytopenia. Additional imaging studies showed multiorgan involvement, including pneumonia, pyelonephritis, and splenomegaly. A bone marrow biopsy of her iliac crest showed hemophagocytosis and the infectious workup confirmed cytomegalovirus (CMV) infection, which led to the diagnosis of CMV-induced HLH. She was treated initially with anakinra for macrophage activation syndrome (MAS) in addition to dexamethasone and ganciclovir. Unfortunately, she did not respond to anakinra and was subsequently switched to etoposide with dexamethasone and valganciclovir, which subsequently helped our patient to recover clinically. Our case highlights the challenging nature of HLH and the importance of early detection and a personalized treatment plan in achieving optimal outcomes in patients with HLH.

17.
Arthritis Rheumatol ; 72(7): 1059-1063, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32293098

RESUMEN

Poor outcomes in COVID-19 correlate with clinical and laboratory features of cytokine storm syndrome. Broad screening for cytokine storm and early, targeted antiinflammatory therapy may prevent immunopathology and could help conserve limited health care resources. While studies are ongoing, extrapolating from clinical experience in cytokine storm syndromes may benefit the multidisciplinary teams caring for patients with severe COVID-19.


Asunto(s)
Antiinflamatorios/uso terapéutico , Infecciones por Coronavirus/inmunología , Síndrome de Liberación de Citoquinas/tratamiento farmacológico , Síndrome de Liberación de Citoquinas/virología , Neumonía Viral/inmunología , Betacoronavirus , Biomarcadores , COVID-19 , Infecciones por Coronavirus/complicaciones , Infecciones por Coronavirus/terapia , Síndrome de Liberación de Citoquinas/diagnóstico , Intervención Médica Temprana , Humanos , Pandemias , Neumonía Viral/complicaciones , Neumonía Viral/terapia , SARS-CoV-2
18.
J Immunol ; 204(10): 2641-2650, 2020 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-32253245

RESUMEN

Although STAT1 tyrosine-701 phosphorylation (designated STAT1-pY701) is indispensable for STAT1 function, the requirement for STAT1 serine-727 phosphorylation (designated STAT1-pS727) during systemic autoimmune and antipathogen responses remains unclear. Using autoimmune-prone B6.Sle1b mice expressing a STAT1-S727A mutant in which serine is replaced by alanine, we report in this study that STAT1-pS727 promotes autoimmune Ab-forming cell (AFC) and germinal center (GC) responses, driving autoantibody production and systemic lupus erythematosus (SLE) development. In contrast, STAT1-pS727 is not required for GC, T follicular helper cell (Tfh), and Ab responses to various foreign Ags, including pathogens. STAT1-pS727 is also not required for gut microbiota and dietary Ag-driven GC and Tfh responses in B6.Sle1b mice. By generating B cell-specific bone marrow chimeras, we demonstrate that STAT1-pS727 plays an important B cell-intrinsic role in promoting autoimmune AFC, GC, and Tfh responses, leading to SLE-associated autoantibody production. Our analysis of the TLR7-accelerated B6.Sle1b.Yaa SLE disease model expressing a STAT1-S727A mutant reveals STAT1-pS727-mediated regulation of autoimmune AFC and GC responses and lupus nephritis development. Together, we identify previously unrecognized differential regulation of systemic autoimmune and antipathogen responses by STAT1-pS727. Our data implicate STAT1-pS727 as a therapeutic target for SLE without overtly affecting STAT1-mediated protection against pathogenic infections.


Asunto(s)
Linfocitos B/inmunología , Centro Germinal/inmunología , Lupus Eritematoso Sistémico/metabolismo , Factor de Transcripción STAT1/metabolismo , Linfocitos T Colaboradores-Inductores/inmunología , Animales , Autoanticuerpos/sangre , Autoantígenos/inmunología , Autoinmunidad , Linfocitos B/trasplante , Humanos , Lupus Eritematoso Sistémico/genética , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Fosforilación , Dominios Proteicos/genética , Factor de Transcripción STAT1/genética , Serina/genética , Activación Transcripcional , Quimera por Trasplante
19.
J Immunol ; 204(4): 796-809, 2020 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-31900342

RESUMEN

TLR7 is associated with development of systemic lupus erythematosus (SLE), but the underlying mechanisms are incompletely understood. Although TLRs are known to activate type I IFN (T1IFN) signaling, the role of T1IFN and IFN-γ signaling in differential regulation of TLR7-mediated Ab-forming cell (AFC) and germinal center (GC) responses, and SLE development has never been directly investigated. Using TLR7-induced and TLR7 overexpression models of SLE, we report in this study a previously unrecognized indispensable role of TLR7-induced IFN-γ signaling in promoting AFC and GC responses, leading to autoreactive B cell and SLE development. T1IFN signaling in contrast, only modestly contributed to autoimmune responses and the disease process in these mice. TLR7 ligand imiquimod treated IFN-γ reporter mice show that CD4+ effector T cells including follicular helper T (Tfh) cells are the major producers of TLR7-induced IFN-γ. Transcriptomic analysis of splenic tissues from imiquimod-treated autoimmune-prone B6.Sle1b mice sufficient and deficient for IFN-γR indicates that TLR7-induced IFN-γ activates multiple signaling pathways to regulate TLR7-promoted SLE. Conditional deletion of Ifngr1 gene in peripheral B cells further demonstrates that TLR7-driven autoimmune AFC, GC and Tfh responses and SLE development are dependent on IFN-γ signaling in B cells. Finally, we show crucial B cell-intrinsic roles of STAT1 and T-bet in TLR7-driven GC, Tfh and plasma cell differentiation. Altogether, we uncover a nonredundant role for IFN-γ and its downstream signaling molecules STAT1 and T-bet in B cells in promoting TLR7-driven AFC, GC, and SLE development whereas T1IFN signaling moderately contributes to these processes.


Asunto(s)
Autoinmunidad/inmunología , Linfocitos B/inmunología , Interferón gamma/inmunología , Lupus Eritematoso Sistémico/inmunología , Activación de Linfocitos/inmunología , Transducción de Señal/inmunología , Animales , Centro Germinal/inmunología , Interferón Tipo I , Glicoproteínas de Membrana/inmunología , Ratones , Receptor Toll-Like 7/inmunología
20.
Front Immunol ; 10: 2608, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31781110

RESUMEN

Infections are considered important environmental triggers of autoimmunity and can contribute to autoimmune disease onset and severity. Nucleic acids and the complexes that they form with proteins-including chromatin and ribonucleoproteins-are the main autoantigens in the autoimmune disease systemic lupus erythematosus (SLE). How these nuclear molecules become available to the immune system for recognition, presentation, and targeting is an area of research where complexities remain to be disentangled. In this review, we discuss how bacterial infections participate in the exposure of nuclear autoantigens to the immune system in SLE. Infections can instigate pro-inflammatory cell death programs including pyroptosis and NETosis, induce extracellular release of host nuclear autoantigens, and promote their recognition in an immunogenic context by activating the innate and adaptive immune systems. Moreover, bacterial infections can release bacterial DNA associated with other bacterial molecules, complexes that can elicit autoimmunity by acting as innate stimuli of pattern recognition receptors and activating autoreactive B cells through molecular mimicry. Recent studies have highlighted SLE disease activity-associated alterations of the gut commensals and the expansion of pathobionts that can contribute to chronic exposure to extracellular nuclear autoantigens. A novel field in the study of autoimmunity is the contribution of bacterial biofilms to the pathogenesis of autoimmunity. Biofilms are multicellular communities of bacteria that promote colonization during chronic infections. We review the very recent literature highlighting a role for bacterial biofilms, and their major components, amyloid/DNA complexes, in the generation of anti-nuclear autoantibodies and their ability to stimulate the autoreactive immune response. The best studied bacterial amyloid is curli, produced by enteric bacteria that commonly cause infections in SLE patients, including Escherichia coli and Salmonella spps. Evidence suggests that curli/DNA complexes can trigger autoimmunity by acting as danger signals, molecular mimickers, and microbial chaperones of nucleic acids.


Asunto(s)
Autoantígenos/inmunología , Infecciones Bacterianas/inmunología , Lupus Eritematoso Sistémico/inmunología , Animales , Autoinmunidad , Infecciones Bacterianas/epidemiología , Biopelículas , Muerte Celular , Núcleo Celular/inmunología , Humanos , Lupus Eritematoso Sistémico/epidemiología , Microbiota , Imitación Molecular
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