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1.
J Pediatric Infect Dis Soc ; 12(9): 487-495, 2023 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-37589394

RESUMEN

BACKGROUND: Adjunctive diagnostic studies (aDS) are recommended to identify occult dissemination in patients with candidemia. Patterns of evaluation with aDS across pediatric settings are unknown. METHODS: Candidemia episodes were included in a secondary analysis of a multicenter comparative effectiveness study that prospectively enrolled participants age 120 days to 17 years with invasive candidiasis (predominantly candidemia) from 2014 to 2017. Ophthalmologic examination (OE), abdominal imaging (AbdImg), echocardiogram, neuroimaging, and lumbar puncture (LP) were performed per clinician discretion. Adjunctive diagnostic studies performance and positive results were determined per episode, within 30 days from candidemia onset. Associations of aDS performance with episode characteristics were evaluated via mixed-effects logistic regression. RESULTS: In 662 pediatric candidemia episodes, 490 (74%) underwent AbdImg, 450 (68%) OE, 426 (64%) echocardiogram, 160 (24%) neuroimaging, and 76 (11%) LP; performance of each aDS per episode varied across sites up to 16-fold. Longer durations of candidemia were associated with undergoing OE, AbdImg, and echocardiogram. Immunocompromised status (58% of episodes) was associated with undergoing AbdImg (adjusted odds ratio [aOR] 2.38; 95% confidence intervals [95% CI] 1.51-3.74). Intensive care at candidemia onset (30% of episodes) was associated with undergoing echocardiogram (aOR 2.42; 95% CI 1.51-3.88). Among evaluated episodes, positive OE was reported in 15 (3%), AbdImg in 30 (6%), echocardiogram in 14 (3%), neuroimaging in 9 (6%), and LP in 3 (4%). CONCLUSIONS: Our findings show heterogeneity in practice, with some clinicians performing aDS selectively, potentially influenced by clinical factors. The low frequency of positive results suggests that targeted application of aDS is warranted.


Asunto(s)
Candidemia , Candidiasis Invasiva , Humanos , Niño , Anciano de 80 o más Años , Candidemia/diagnóstico , Candidemia/microbiología , Candidiasis Invasiva/tratamiento farmacológico , Modelos Logísticos , Estudios de Cohortes , Factores de Riesgo , Antifúngicos/uso terapéutico
2.
Pediatrics ; 150(4)2022 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-36156158

RESUMEN

Head lice infestation is associated with limited morbidity but causes a high level of anxiety among caregivers of school-aged children and adolescents. Since the 2015 clinical report on head lice was published by the American Academy of Pediatrics, new medications have been approved, and an algorithm for management of affected patients is included. This revised clinical report clarifies current diagnosis and treatment protocols.


Asunto(s)
Infestaciones por Piojos , Pediculus , Dermatosis del Cuero Cabelludo , Adolescente , Animales , Cuidadores , Niño , Humanos , Infestaciones por Piojos/tratamiento farmacológico , Infestaciones por Piojos/terapia , Dermatosis del Cuero Cabelludo/diagnóstico , Dermatosis del Cuero Cabelludo/terapia
3.
JAMA Pediatr ; 176(7): 690-698, 2022 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-35499841

RESUMEN

Importance: Blood culture overuse in the pediatric intensive care unit (PICU) can lead to unnecessary antibiotic use and contribute to antibiotic resistance. Optimizing blood culture practices through diagnostic stewardship may reduce unnecessary blood cultures and antibiotics. Objective: To evaluate the association of a 14-site multidisciplinary PICU blood culture collaborative with culture rates, antibiotic use, and patient outcomes. Design, Setting, and Participants: This prospective quality improvement (QI) collaborative involved 14 PICUs across the United States from 2017 to 2020 for the Bright STAR (Testing Stewardship for Antibiotic Reduction) collaborative. Data were collected from each participating PICU and from the Children's Hospital Association Pediatric Health Information System for prespecified primary and secondary outcomes. Exposures: A local QI program focusing on blood culture practices in the PICU (facilitated by a larger QI collaborative). Main Outcomes and Measures: The primary outcome was blood culture rates (per 1000 patient-days/mo). Secondary outcomes included broad-spectrum antibiotic use (total days of therapy and new initiations of broad-spectrum antibiotics ≥3 days after PICU admission) and PICU rates of central line-associated bloodstream infection (CLABSI), Clostridioides difficile infection, mortality, readmission, length of stay, sepsis, and severe sepsis/septic shock. Results: Across the 14 PICUs, the blood culture rate was 149.4 per 1000 patient-days/mo preimplementation and 100.5 per 1000 patient-days/mo postimplementation, for a 33% relative reduction (95% CI, 26%-39%). Comparing the periods before and after implementation, the rate of broad-spectrum antibiotic use decreased from 506 days to 440 days per 1000 patient-days/mo, respectively, a 13% relative reduction (95% CI, 7%-19%). The broad-spectrum antibiotic initiation rate decreased from 58.1 to 53.6 initiations/1000 patient-days/mo, an 8% relative reduction (95% CI, 4%-11%). Rates of CLABSI decreased from 1.8 to 1.1 per 1000 central venous line days/mo, a 36% relative reduction (95% CI, 20%-49%). Mortality, length of stay, readmission, sepsis, and severe sepsis/septic shock were similar before and after implementation. Conclusions and Relevance: Multidisciplinary diagnostic stewardship interventions can reduce blood culture and antibiotic use in the PICU. Future work will determine optimal strategies for wider-scale dissemination of diagnostic stewardship in this setting while monitoring patient safety and balancing measures.


Asunto(s)
Sepsis , Choque Séptico , Antibacterianos/uso terapéutico , Cultivo de Sangre , Niño , Enfermedad Crítica , Humanos , Unidades de Cuidado Intensivo Pediátrico , Estudios Prospectivos , Sepsis/diagnóstico , Sepsis/tratamiento farmacológico , Estados Unidos
4.
Pediatrics ; 149(2)2022 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-35104357

RESUMEN

The purpose of this report is to educate providers about the risk of infectious diseases associated with emerging alternative peripartum and neonatal practices. This report will provide information pediatricians may use to counsel families before birth and to appropriately evaluate and treat neonates who have been exposed to these practices.


Asunto(s)
Terapias Complementarias/tendencias , Salud del Lactante/tendencias , Complicaciones Infecciosas del Embarazo/diagnóstico , Complicaciones Infecciosas del Embarazo/epidemiología , Enfermedades Transmisibles/diagnóstico , Enfermedades Transmisibles/epidemiología , Enfermedades Transmisibles/transmisión , Terapias Complementarias/efectos adversos , Femenino , Humanos , Recién Nacido , Embarazo , Factores de Riesgo
6.
Pediatrics ; 148(6)2021 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-34851422

RESUMEN

Tuberculosis (TB) remains an important problem among children in the United States and throughout the world. There is no diagnostic reference standard for latent tuberculosis infection (also referred to as tuberculosis infection [TBI]). The tuberculin skin test (TST) has many limitations, including difficulty in administration and interpretation, the need for a return visit by the patient, and false-positive results caused by cross-reaction with Mycobacterium bovis-bacille Calmette-Guerin vaccines and many nontuberculous mycobacteria. Interferon-gamma release assays (IGRAs) are blood tests that use antigens specific for M tuberculosis; as a result, IGRAs yield fewer false-positive results than the TST. Both IGRAs and the TST have reduced sensitivity in immunocompromised children, including children with severe TB disease. Both methods have high positive predictive value when applied to children with risk factors for TBI, especially recent contact with a person who has TB disease. The advantages of using IGRAs and diminished experience with the placement and interpretation of the TST favor expanded use of IGRAs in children in the United States. There are now several effective and safe regimens for the treatment of TBI in children. For improved adherence to therapy, the 3 rifamycin-based regimens are preferred because of their short duration. Daily isoniazid can be used if there is intolerance or drug interactions with rifamycins. A TB specialist should be involved when there are questions regarding testing interpretation, selection of an appropriate treatment regimen, or management of adverse effects.


Asunto(s)
Antituberculosos/uso terapéutico , Ensayos de Liberación de Interferón gamma/métodos , Tuberculosis Latente/diagnóstico , Tuberculosis Latente/tratamiento farmacológico , Prueba de Tuberculina/métodos , Adolescente , Factores de Edad , Antituberculosos/efectos adversos , Vacuna BCG/inmunología , Niño , Preescolar , Reacciones Cruzadas , Reacciones Falso Positivas , Humanos , Huésped Inmunocomprometido/inmunología , Lactante , Isoniazida/uso terapéutico , Mycobacterium bovis/inmunología , Mycobacterium tuberculosis/inmunología , Micobacterias no Tuberculosas/inmunología , Rifampin/análogos & derivados , Rifampin/uso terapéutico , Sensibilidad y Especificidad
7.
Artículo en Inglés | MEDLINE | ID: mdl-34374424

RESUMEN

BACKGROUND: Invasive candidiasis is the most common invasive fungal disease in children and adolescents, but there are limited pediatric-specific antifungal effectiveness data. We compared the effectiveness of echinocandins to triazoles or amphotericin B formulations (triazole/amphotericin B) as initial directed therapy for invasive candidiasis. METHODS: This multinational observational cohort study enrolled patients aged >120 days and <18 years with proven invasive candidiasis from January 1, 2014, to November 28, 2017, at 43 International Pediatric Fungal Network sites. Primary exposure was initial directed therapy administered at the time qualifying culture became positive for yeast. Exposure groups were categorized by receipt of an echinocandin vs receipt of triazole/amphotericin B. Primary outcome was global response at 14 days following invasive candidiasis onset, adjudicated by a centralized data review committee. Stratified Mantel-Haenszel analyses estimated risk difference between exposure groups. RESULTS: Seven-hundred and fifty invasive candidiasis episodes were identified. After exclusions, 541 participants (235 in the echinocandin group and 306 in the triazole/amphotericin B group) remained. Crude failure rates at 14 days for echinocandin and triazole/amphotericin B groups were 9.8% (95% confidence intervals [CI]: 6.0% to 13.6%) and 13.1% (95% CI: 9.3% to 16.8%), respectively. The adjusted 14-day risk difference between echinocandin and triazole/amphotericin B groups was -7.1% points (95% CI: -13.1% to -2.4%), favoring echinocandins. The risk difference was -0.4% (95% CI: -7.5% to 6.7%) at 30 days. CONCLUSIONS: In children with invasive candidiasis, initial directed therapy with an echinocandin was associated with reduced failure rate at 14 days but not 30 days. These results may support echinocandins as initial directed therapy for invasive candidiasis in children and adolescents. CLINICAL TRIALS REGISTRATION: NCT01869829.

8.
Pediatr Rev ; 42(2): 68-77, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33526572

RESUMEN

Encephalitis is defined as altered mental status for more than 24 hours accompanied by 2 or more findings concerning for inflammation of the brain parenchyma: fever, seizures or other focal neurologic disorders, cerebrospinal fluid pleocytosis, and abnormal neuroimaging and electroencephalographic findings. Herpes simplex virus causes the most severe form of virus-induced encephalitis; the early administration of acyclovir can improve the prognosis of this disease. The rising interest in autoimmune causes of encephalitis, most notably anti-N-methyl-d-aspartate receptor, should prompt the clinician to consider immunomodulatory treatments, which may improve outcomes. A broad testing panel may be necessary to detect the etiologic agent; a few published pediatric cases suggest that infectious and autoimmune causes may occur concurrently in the same patient with encephalitis. More than 40% of children diagnosed as having encephalitis will not return to their previous level of neurologic function after resolution of their disease, although outcomes are highly variable depending on the etiologic agent.


Asunto(s)
Encefalitis/diagnóstico , Antiinfecciosos/uso terapéutico , Encéfalo/diagnóstico por imagen , Niño , Diagnóstico Diferencial , Encefalitis/tratamiento farmacológico , Encefalitis/inmunología , Encefalitis/virología , Humanos , Factores Inmunológicos/uso terapéutico , Neuroimagen
9.
Curr Opin Pediatr ; 32(4): 610-618, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32618790

RESUMEN

PURPOSE OF REVIEW: The present coronavirus disease 2019 (COVID-19) pandemic has created additional challenges with an increased number of presumed healthy, full-term newborns being discharged at 24 h after delivery. Short lengths of stay raise the possibility of mother-infant dyads being less ready for discharge, defined as at least one of the three informants (i.e., mother, pediatrician, and obstetrician) believing that either the mother and/or infant should stay longer than the proposed time of discharge. This public health crisis has reduced the number of in-person well child visits, negatively impacting vaccine receipt, and anticipatory guidance. RECENT FINDINGS: Extra precautions should be taken during the transition period between postpartum discharge and follow-up in the ambulatory setting to ensure the safety of all patients and practice team members. This should include restructuring office flow by visit type and location, limiting in-person visits during well infant exams, instituting proper procedures for personal protective equipment and for cleaning of the office, expanding telehealth capabilities for care and education, and prioritizing universal vaccinations and routine well child screenings. SUMMARY: Based on current limited evidence, this report provides guidance for the postdischarge management of newborns born to mothers with confirmed or suspected disease in the ambulatory setting as well as prioritizing universal immunizations and routine well child screenings during the COVID-19 pandemic.


Asunto(s)
Infecciones por Coronavirus , Coronavirus , Cuidado del Lactante , Pandemias , Alta del Paciente , Neumonía Viral , Betacoronavirus , COVID-19 , Niño , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/prevención & control , Femenino , Humanos , Cuidado del Lactante/normas , Recién Nacido , Pandemias/prevención & control , Neumonía Viral/epidemiología , Neumonía Viral/prevención & control , Periodo Posparto , SARS-CoV-2
10.
J Pediatr Surg ; 55(7): 1339-1343, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31515110

RESUMEN

BACKGROUND: The infectious risk of central venous line (CVL) placement in children with neutropenia (absolute neutrophil count [ANC] <500/mm3) is not well defined. This study aims to investigate the early (≤30 days) and late (>30 days) infectious complications of CVLs placed in pediatric patients with and without neutropenia. METHODS: A retrospective review was conducted of all CVLs placed by pediatric surgeons at two institutions from 2010 to 2017. Multivariable logistic regression was performed to identify risk factors for line infection. Propensity score-matched cohorts of patients with and without neutropenia were compared in a 1:1 ratio. Wilcoxon rank-sum, Chi-square, Fisher's exact, and log-rank tests were also performed. RESULTS: Review identified 1,102 CVLs placed in 937 patients. Fifty-four patients were neutropenic at the time of placement. Multivariable analysis demonstrated tunneled catheters and subclavian access as associated with line infection. The propensity score-matched cohort included 94 patients, 47 from each group. Demographic and preoperative data were similar between the groups (p > 0.05). Patients with neutropenia were no more likely to develop early (4.3% vs. 2.1%, p = 1.000) or late (19.1% vs. 17.0%, p = 1.000) infectious complications than patients without neutropenia, with similar median time to infection (141 vs. 222 days, p = 0.370). CONCLUSION: A policy of selective CVL placement in neutropenic patients with standardized postoperative line maintenance is safe. Future directions include defining criteria by which neutropenic patients could be prospectively selected for safe CVL placement. LEVEL OF EVIDENCE: II - Retrospective cohort study.


Asunto(s)
Infecciones Relacionadas con Catéteres/epidemiología , Cateterismo Venoso Central/efectos adversos , Neutropenia/epidemiología , Complicaciones Posoperatorias/epidemiología , Niño , Humanos , Periodo Perioperatorio , Puntaje de Propensión , Estudios Retrospectivos , Factores de Riesgo
12.
Pediatr Rev ; 39(6): 287-298, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29858291

RESUMEN

Staphylococcus aureus is a bacterium that can cause a variety of illnesses through suppurative or nonsuppurative (toxin-mediated) means. S aureus is a common cause of skin and skin structure infections as well as osteoarticular infections in the pediatric population. S aureus is also identified in cases of septicemia, infective endocarditis, pneumonia, ocular infections, and central nervous system infections. To design appropriate empirical therapy, pediatricians should be knowledgeable about the resistance patterns of S aureus in their communities, including methicillin and clindamycin resistance. This article reviews the microbiology, colonization and transmission, and antibiotic resistance of and clinical diseases caused by S aureus.


Asunto(s)
Antibacterianos/uso terapéutico , Farmacorresistencia Bacteriana/efectos de los fármacos , Infecciones Estafilocócicas/diagnóstico , Staphylococcus aureus , Niño , Humanos , Infecciones Estafilocócicas/tratamiento farmacológico
13.
Clin Med Insights Pediatr ; 10: 57-65, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27429564

RESUMEN

Cystic fibrosis (CF) is a chronic disorder characterized by acute pulmonary exacerbations that comprise increased cough, chest congestion, increased mucus production, shortness of breath, weight loss, and fatigue. Typically, severe episodes are treated in the inpatient setting and include intravenous antimicrobials, airway clearance therapy, and nutritional support. Children with less-severe findings can often be managed as outpatients with oral antimicrobials and increased airway clearance therapy at home without visiting the specialty CF center to begin treatment. Selection of specific antimicrobial agents is dependent on pathogens found in surveillance culture, activity of an agent in patients with CF, and the unique physiology of these patients. In this pediatric review, we present our practice for defining acute pulmonary exacerbation, deciding treatment location, initiating treatment either in-person or remotely, determining the frequency of airway clearance, selecting antimicrobial therapy, recommending timing for follow-up visit, and recognizing and managing treatment failures.

14.
Pediatr Dermatol ; 32(3): e70-3, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25727569

RESUMEN

Multicentric reticulohistiocytosis (MRH) is a rare systemic inflammatory granulomatous disease marked by severe and often rapidly progressive polyarticular arthritis and cutaneous papulonodules. Initial clinical diagnosis may be difficult. We describe a 2-year-old girl presenting with pink dermal papules on the forehead, thighs, elbows, knees, and palms of the hands. Based on clinical findings and skin biopsy results, she was initially diagnosed with granuloma annulare. At 5 years of age, she developed arthritis, fatigue, and more widespread skin papules leading to the diagnosis of MRH. To our knowledge, this is the youngest individual with MRH yet described. We outline the timeline and unique features of her case and review the literature pertaining to MRH in children. Although rare, MRH can be permanently debilitating, making prompt diagnosis critical. A standardized approach to investigation and management needs to be developed.


Asunto(s)
Histiocitosis de Células no Langerhans/diagnóstico , Biopsia , Fármacos Dermatológicos/uso terapéutico , Diagnóstico Diferencial , Femenino , Histiocitosis de Células no Langerhans/tratamiento farmacológico , Humanos , Lactante , Infliximab/uso terapéutico
15.
Pediatr Blood Cancer ; 62(7): 1149-54, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25728418

RESUMEN

BACKGROUND: Treatment of acute myeloid leukemia (AML) comes with a significant risk of life-threatening infection during periods of prolonged severe neutropenia. We studied the impact of preventive intravenous (IV) antibiotic administration at onset of absolute neutropenia on the incidence and outcome of life-threatening infections during treatment of childhood AML. PROCEDURES: This is a retrospective study on pediatric patients (aged 0-18 years) consecutively diagnosed with de novo AML and treated at a single institution from April 2005 through February 2013. Patients were treated on the Children's Oncology Group (COG) AAML0531 protocol or with a modified United Kingdom Medical Research Council (UK MRC) AML 10 regimen. Pertinent data were extracted from hard copy or electronic chart review. RESULTS: A total of 76 chemotherapy phases were analyzed from 29 patients. In each phase reported, preventive antibiotics were initiated when the daily absolute neutrophil count was <500 cells/mcl, before onset of fever. Seven episodes of bacteremia were documented with predominantly coagulase-negative staphylococci and viridans group streptococci. One infection-related death occurred, attributed to progressive respiratory failure occurring months after documented candidal pneumonia. CONCLUSIONS: Initiation of preventive antibiotics at the onset of absolute neutropenia was associated with no mortality from bacteremia. This preventive approach appears feasible and safe.


Asunto(s)
Antibacterianos/uso terapéutico , Leucemia Mieloide Aguda/complicaciones , Infecciones Oportunistas/prevención & control , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Lactante , Recién Nacido , Leucemia Mieloide Aguda/microbiología , Masculino , Estadificación de Neoplasias , Infecciones Oportunistas/etiología , Pronóstico , Estudios Retrospectivos
16.
Pediatr Dermatol ; 31(6): 716-21, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-23405946

RESUMEN

Osteopetrosis, lymphedema, hypohidrotic ectodermal dysplasia, and immunodeficiency (OL-HED-ID) is a rare X-linked disorder with only three reported prior cases in the English-language literature. We describe a case of OL-HED-ID in a male infant who initially presented with congenital lymphedema, leukocytosis, and thrombocytopenia of unknown etiology at 7 days of age. He subsequently developed gram-negative sepsis and multiple opportunistic infections including high-level cytomegalovirus viremia and Pneumocystis jiroveci pneumonia. The infant was noted to have mildly xerotic skin, fine sparse hair, and periorbital wrinkling, all features suggestive of ectodermal dysplasia. Skeletal imaging showed findings consistent with osteopetrosis, and immunologic investigation revealed hypogammaglobulinemia and mixed T- and B-cell dysfunction. Genetic testing revealed a novel mutation in the nuclear factor kappa beta (NF-KB) essential modulator (NEMO) gene, confirming the diagnosis of OL-HED-ID. Mutations in the NEMO gene have been reported in association with hypohidrotic ectodermal dysplasia with immunodeficiency (HED-ID), OL-HED-ID, and incontinentia pigmenti. In this case, we report a novel mutation in the NEMO gene associated with OL-HED-ID. This article highlights the dermatologic manifestations of a rare disorder, OL-HED-ID, and underscores the importance of early recognition and prompt intervention to prevent life-threatening infections.


Asunto(s)
Displasia Ectodermal Anhidrótica Tipo 1/complicaciones , Displasia Ectodérmica/complicaciones , Enfermedades Genéticas Ligadas al Cromosoma X/complicaciones , Síndromes de Inmunodeficiencia/complicaciones , Linfedema/complicaciones , Infecciones Oportunistas/complicaciones , Osteopetrosis/complicaciones , Displasia Ectodérmica/genética , Displasia Ectodérmica/terapia , Displasia Ectodermal Anhidrótica Tipo 1/genética , Displasia Ectodermal Anhidrótica Tipo 1/terapia , Enfermedades Genéticas Ligadas al Cromosoma X/genética , Enfermedades Genéticas Ligadas al Cromosoma X/terapia , Humanos , Síndromes de Inmunodeficiencia/genética , Síndromes de Inmunodeficiencia/terapia , Recién Nacido , Linfedema/genética , Linfedema/terapia , Masculino , Infecciones Oportunistas/genética , Infecciones Oportunistas/terapia , Osteopetrosis/genética , Osteopetrosis/terapia , Enfermedades de Inmunodeficiencia Primaria
17.
PLoS Pathog ; 5(4): e1000374, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19360129

RESUMEN

Mycobacterium tuberculosis (Mtb) resides in a long-lived phagosomal compartment that resists maturation. The manner by which Mtb antigens are processed and presented on MHC Class I molecules is poorly understood. Using human dendritic cells and IFN-gamma release by CD8(+) T cell clones, we examined the processing and presentation pathway for two Mtb-derived antigens, each presented by a distinct HLA-I allele (HLA-Ia versus HLA-Ib). Presentation of both antigens is blocked by the retrotranslocation inhibitor exotoxin A. Inhibitor studies demonstrate that, after reaching the cytosol, both antigens require proteasomal degradation and TAP transport, but differ in the requirement for ER-golgi egress and new protein synthesis. Specifically, presentation by HLA-B8 but not HLA-E requires newly synthesized HLA-I and transport through the ER-golgi. Phenotypic analysis of the Mtb phagosome by flow organellometry revealed the presence of Class I and loading accessory molecules, including TAP and PDI. Furthermore, loaded HLA-I:peptide complexes are present within the Mtb phagosome, with a pronounced bias towards HLA-E:peptide complexes. In addition, protein analysis also reveals that HLA-E is enriched within the Mtb phagosome compared to HLA-A2. Together, these data suggest that the phagosome, through acquisition of ER-localized machinery and as a site of HLA-I loading, plays a vital role in the presentation of Mtb-derived antigens, similar to that described for presentation of latex bead-associated antigens. This is, to our knowledge, the first description of this presentation pathway for an intracellular pathogen. Moreover, these data suggest that HLA-E may play a unique role in the presentation of phagosomal antigens.


Asunto(s)
Presentación de Antígeno/fisiología , Antígenos Bacterianos/metabolismo , Antígenos de Histocompatibilidad Clase I/metabolismo , Mycobacterium tuberculosis/inmunología , Fagosomas/metabolismo , Antígenos Bacterianos/inmunología , Western Blotting , Linfocitos T CD8-positivos/inmunología , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Citometría de Flujo , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Interferón gamma/biosíntesis , Interferón gamma/inmunología , Activación de Linfocitos/inmunología , Mycobacterium tuberculosis/metabolismo , Fagosomas/inmunología
18.
J Immunol ; 175(2): 1107-17, 2005 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-16002712

RESUMEN

The primary goal of this study was to determine how chronic exposure to Ag influences the functionality of Mycobacterium tuberculosis-specific T cell responses. The frequency of IFN-gamma-producing effector CD4(+) and CD8(+) T cells dynamically changed during persistent M. tuberculosis infection. CD8(+) T cells used differential effector functions during acute and chronic phases of the immune response, where CD8(+) T cells produced negligible amounts of IFN-gamma early in infection, but switched to cytokine production during the chronic stage of infection. Using limiting dilution analysis, CD8(+) T cells isolated during the initial phase of infection demonstrated lytic potential, but this waned in the chronic stage. The apparent loss of cytotoxic activity was not associated with the lack of perforin. Ag dose could potentially govern the functional program of CD8(+) T cells. Collectively, these results depict a host immune response mounted against M. tuberculosis of a significantly more dynamic nature than previously recognized.


Asunto(s)
Mycobacterium tuberculosis/inmunología , Tuberculosis Pulmonar/inmunología , Tuberculosis Pulmonar/prevención & control , Enfermedad Aguda , Animales , Antígenos Bacterianos/inmunología , Antígenos Bacterianos/metabolismo , Apoptosis/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/patología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/patología , Proliferación Celular , Células Cultivadas , Enfermedad Crónica , Pruebas Inmunológicas de Citotoxicidad , Epítopos de Linfocito T/metabolismo , Interferón gamma/biosíntesis , Activación de Linfocitos/inmunología , Recuento de Linfocitos , Ratones , Ratones Endogámicos C57BL , Mycobacterium tuberculosis/crecimiento & desarrollo , Factores de Tiempo , Tuberculosis Pulmonar/patología
19.
Pediatrics ; 114(6): 1673-5, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15574633

RESUMEN

Reports of clinical manifestations of West Nile virus (WNV) infections in children have been relatively rare. Four cases of WNV infection in children are described: the first report of prolonged encephalitis and fulminant hepatitis caused by WNV, and 3 other presentations of WNV, including the first report of ocular involvement in a child.


Asunto(s)
Convulsiones/etiología , Trastornos de la Visión/etiología , Fiebre del Nilo Occidental/complicaciones , Virus del Nilo Occidental/aislamiento & purificación , Adolescente , Niño , Oftalmopatías/etiología , Infecciones Virales del Ojo , Femenino , Fiebre/etiología , Escala de Coma de Glasgow , Cefalea/etiología , Humanos , Fallo Hepático Agudo/etiología , Masculino , Pars Planitis/etiología , Cuerpo Vítreo , Vómitos/etiología , Fiebre del Nilo Occidental/diagnóstico
20.
Infect Immun ; 72(5): 2976-88, 2004 May.
Artículo en Inglés | MEDLINE | ID: mdl-15102810

RESUMEN

Alternate modalities for the treatment of Mycobacterium tuberculosis are needed due to the rise in numbers of immunosuppressed individuals at risk for serious disease and the increasing prevalence of multidrug-resistant isolates. Interleukin-12 (IL-12) has been shown to improve immune responses against M. tuberculosis infection in both humans and mice. Previous studies using high-dose IL-12 in various disease models reported a paradoxical immunosuppression. We demonstrate here that exogenous administration of IL-12 for 8 weeks after an aerosolized low dose of M. tuberculosis results in increased survival and decreased pulmonary bacterial loads for CD4-T-cell-deficient mice, most likely due to an early increase in gamma interferon. IL-12 treatment did not impair or enhance the ability of the wild-type mice to control infection, as measured by bacterial numbers. Two novel findings are reported here regarding exogenous IL-12 therapy for M. tuberculosis infections: (i). IL-12 treatment resulted in decreased numbers of immune cells and reduced frequencies of lymphocytes (CD8(+), CD4(+), and NK cells) in the lungs of infected mice and (ii). IL-12 therapy reduced the pathology of M. tuberculosis-infected lungs, as granulomas were smaller and less numerous. These studies support an immunoregulatory role for IL-12 in tuberculosis.


Asunto(s)
Interleucina-12/uso terapéutico , Tuberculosis Pulmonar/tratamiento farmacológico , Tuberculosis Pulmonar/inmunología , Adyuvantes Inmunológicos/uso terapéutico , Animales , Antígenos CD4/genética , Antígenos CD4/metabolismo , Granuloma/patología , Humanos , Inflamación/patología , Interferón gamma/biosíntesis , Células Asesinas Naturales/efectos de los fármacos , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/patología , Pulmón/efectos de los fármacos , Pulmón/inmunología , Pulmón/patología , Activación de Linfocitos/efectos de los fármacos , Recuento de Linfocitos , Subgrupos Linfocitarios/efectos de los fármacos , Subgrupos Linfocitarios/inmunología , Subgrupos Linfocitarios/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas Recombinantes/uso terapéutico , Subgrupos de Linfocitos T/efectos de los fármacos , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/patología , Tuberculosis Pulmonar/patología
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