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The object of this study was to extensively characterize a region of periventricular nodular heterotopia (PVNH) in an epilepsy patient to reveal its possible neurocognitive functional role(s). The authors used 3-T MRI approaches to exhaustively characterize a single, right hemisphere heterotopion in a high-functioning adult male with medically responsive epilepsy, which had manifested during late adolescence. The heterotopion proved to be spectroscopically consistent with a cortical-like composition and was interconnected with nearby ipsilateral cortical fundi, as revealed by fiber tractography (diffusion-weighted imaging) and resting-state functional connectivity MRI (rsfMRI). Moreover, the region of PVNH demonstrated two novel characterizations for a heterotopion. First, functional MRI (fMRI), as distinct from rsfMRI, showed that the heterotopion was significantly modulated while the patient watched animated video scenes of biological motion (i.e., cartoons). Second, rsfMRI, which demonstrated correlated brain activity during a task-negative state, uniquely showed directionality within an interconnected network, receiving positive path effects from patent cortical and cerebellar foci while outputting only negative path effects to specific brain foci.These findings are addressed in the context of the impact on noninvasive presurgical brain mapping strategies for adult and pediatric patient workups, as well as the impact of this study on an understanding of the functional cortical architecture underlying cognition from a neurodiversity and evolutionary perspective.
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Mapeo Encefálico/métodos , Epilepsia/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Heterotopia Nodular Periventricular/diagnóstico por imagen , Descanso/fisiología , Convulsiones/diagnóstico por imagen , Epilepsia/fisiopatología , Humanos , Masculino , Heterotopia Nodular Periventricular/fisiopatología , Cuidados Preoperatorios/métodos , Convulsiones/fisiopatología , Adulto JovenRESUMEN
In women, breast cancer is the most common cancer diagnosis and second most common cause of cancer death. More than half of breast cancer patients will develop metastases to the bone, liver, lung, or brain. Breast cancer brain metastases (BCBM) confers a poor prognosis, as current therapeutic options of surgery, radiation, and chemotherapy rarely significantly extend life and are considered palliative. Within the realm of chemotherapy, the last decade has seen an explosion of novel chemotherapeutics involving targeting agents and unique dosage forms. We provide a historical overview of BCBM chemotherapy, review the mechanisms of new agents such as poly-ADP ribose polymerase inhibitors, cyclin-dependent kinase 4/6 inhibitors, phosphatidyl inositol 3-kinaseinhibitors, estrogen pathway antagonists for hormone-receptor positive BCBM; tyrosine kinase inhibitors, antibodies, and conjugates for HER2+ BCBM; repurposed cytotoxic chemotherapy for triple negative BCBM; and the utilization of these new agents and formulations in ongoing clinical trials. The mechanisms of novel dosage formulations such as nanoparticles, liposomes, pegylation, the concepts of enhanced permeation and retention, and drugs utilizing these concepts involved in clinical trials are also discussed. These new treatments provide a promising outlook in the treatment of BCBM.
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Antineoplásicos/uso terapéutico , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias de la Mama/tratamiento farmacológico , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/farmacocinética , Barrera Hematoencefálica/metabolismo , Neoplasias Encefálicas/epidemiología , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/secundario , Neoplasias de la Mama/epidemiología , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Sistemas de Liberación de Medicamentos , HumanosRESUMEN
The purpose of this randomized wait-list controlled trial was to test the feasibility and preliminary efficacy of a guided imagery based multi-behavior intervention intended to address psychological stress, food cravings, and physical activity. Personalized guided imagery scripts were created and participants were instructed to practice guided imagery every day for 35 consecutive days. Of 48 women who enrolled, we report comparisons between 16 randomized to treatment with 19 who were wait-listed (overall Mage = 45.50; Mbodymassindex = 31.43). Study completers reported 89% compliance with practicing guided imagery during the intervention. A significant time-by-group interaction was observed with reductions in food cravings and increases in physical activity compared with wait-list controls. Telephone-based multi-behavior interventions that utilize guided imagery to address food cravings and exercise behavior appear to be acceptable for overweight and obese women. Future phone-based guided imagery research testing this skill to address multiple health behaviors is justified.
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Ansia , Ejercicio Físico/psicología , Preferencias Alimentarias/psicología , Imágenes en Psicoterapia , Obesidad/terapia , Sobrepeso/terapia , Estrés Psicológico/terapia , Adulto , Estudios de Factibilidad , Femenino , Conductas Relacionadas con la Salud , Humanos , Persona de Mediana Edad , Obesidad/psicología , Sobrepeso/psicología , Autonomía Personal , Estrés Psicológico/complicaciones , Estrés Psicológico/psicologíaRESUMEN
The sensitivity of the eye at night would lead to complete saturation of the eye during the day. Therefore, the sensitivity of the eye must be down-regulated during the day to maintain visual acuity. In the Drosophila eye, the opening of TRP and TRPL channels leads to an influx of Ca++ that triggers down-regulation of further responses to light, including the movement of the TRPL channel and Gα proteins out of signaling complexes found in actin-mediated microvillar extensions of the photoreceptor cells (the rhabdomere). The eye also exhibits a light entrained-circadian rhythm, and we have recently observed that one component of this rhythm (BDBT) becomes undetectable by antibodies after exposure to light even though immunoblot analyses still detect it in the eye. BDBT is necessary for normal circadian rhythms, and in several circadian and visual mutants this eye-specific oscillation of detection is lost. Many phototransduction signaling proteins (e.g., Rhodopsin, TRP channels and Gα) also become undetectable shortly after light exposure, most likely due to a light-induced compaction of the rhabdomeric microvilli. The circadian protein BDBT might be involved in light-induced changes in the rhabdomere, and if so this could indicate that circadian clocks contribute to the daily adaptations of the eye to light. Likewise, circadian oscillations of clock proteins are observed in photoreceptors of the mammalian eye and produce a circadian oscillation in the ERG. Disruption of circadian rhythms in the eyes of mammals causes neurodegeneration in the eye, demonstrating the importance of the rhythms for normal eye function.
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BRIDE OF DOUBLETIME (BDBT) interacts with the circadian kinase DOUBLETIME (DBT) and accumulates in eye foci during the dark of a light:dark cycle. BDBT foci are shown here to be broadly expressed in constant dark and low in constant light. Analysis of circadian photoreceptor cry and visual photoreceptor ninaE mutants showed that disappearance of eye BDBT foci requires both the CRYPTOCHROME and the RHODOPSIN-1 pathways. The arr1 and arr2 mutants, which affect rhodopsin quenching, eliminated BDBT foci under dark conditions. arr1 and arr2 mutants also caused increased nuclear PER protein. The changes in BDBT foci do not result from altered BDBT levels in the eye but from changes in its immunodetection. Knockdown of BDBT specifically in the eye produced constitutively nuclear PER and constitutively cytosolic DBT. The results show that BDBT is necessary for co-transport of DBT and PER into the nucleus and suggest that this process is regulated by a light-dependent mechanism.
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We describe a case of an 8 year old girl with central precocious puberty. She was commenced on 3 monthly intramuscular depot Leuprorelin acetate therapy, as a result of which she developed sterile abscesses. She was converted to daily subcutaneous Leuprorelin acetate therapy with no recurrence of the abscesses. The possible mechanisms for this reaction are described in the article.
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Absceso/inducido químicamente , Leuprolida/efectos adversos , Pubertad Precoz/tratamiento farmacológico , Niño , Preparaciones de Acción Retardada , Femenino , Humanos , Inyecciones Intradérmicas/efectos adversos , Leuprolida/administración & dosificación , Leuprolida/uso terapéutico , Pubertad Precoz/diagnósticoRESUMEN
A 44-year-old woman was diagnosed with Graves' disease in 1995 and over the following 12 months developed thyroid dermopathy (pretibial myxoedema). Despite being trialled on multiple recognized therapies over the course of 11 years, the patient's dermopathy progressively worsened. She developed ocular proptosis, elephantiasic thyroid dermopathy and acropachy in both hands. In mid 2006, the patient was started on rituximab and plasmapheresis, with rapid response. The patient's condition stabilized and in October 2009 at the age of 58 years she was able to cease therapy.
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Anticuerpos Monoclonales de Origen Murino/uso terapéutico , Dermatosis de la Mano/terapia , Factores Inmunológicos/uso terapéutico , Dermatosis de la Pierna/terapia , Mixedema/terapia , Plasmaféresis , Adulto , Terapia Combinada/métodos , Femenino , Enfermedad de Graves/complicaciones , Dermatosis de la Mano/etiología , Dermatosis de la Mano/patología , Humanos , Dermatosis de la Pierna/etiología , Dermatosis de la Pierna/patología , Mixedema/etiología , Mixedema/patología , Rituximab , Resultado del TratamientoRESUMEN
Posttraumatic Stress Disorder (PTSD) is a devastating condition that can develop after blast Traumatic Brain Injury (TBI). Ongoing work has been performed to understand how PTSD develops after injury. In this review, we highlight how PTSD affects individuals, discuss what is known about the physiologic changes to the hypothalamic pituitary axis and neurotransmitter pathways, and present an overview of genetic components that may predispose individuals to developing PTSD. We then provide an overview of current treatment strategies to treat PTSD in veterans and present new strategies that may be useful going forward. The need for further clinical and pre-clinical studies is imperative to improve diagnosis, treatment, and management for patients that develop PTSD following blast TBI.
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This case describes a patient in whom cytomegalovirus (CMV) infected a preexisting ulcer. The patient was immune-suppressed because of treatment for Wegener's granulomatosis. Specific antiviral therapy was delayed because of uncertainty as to the role of CMV, but the infection cleared and the ulcer improved promptly on institution of valganciclovir.
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Infecciones por Citomegalovirus/etiología , Granulomatosis con Poliangitis/inmunología , Huésped Inmunocomprometido , Úlcera/virología , Anciano , Antivirales/uso terapéutico , Ganciclovir/análogos & derivados , Ganciclovir/uso terapéutico , Granulomatosis con Poliangitis/tratamiento farmacológico , Humanos , Masculino , Úlcera/tratamiento farmacológico , ValganciclovirRESUMEN
Progressive neurodegenerative diseases plague millions of individuals both in the United States and across the world. The current pathology of progressive neurodegenerative tauopathies, such as Alzheimer's disease (AD), Pick's disease, frontotemporal dementia (FTD), and progressive supranuclear palsy, primarily revolves around phosphorylation and hyperphosphorylation of the tau protein. However, more recent evidence suggests acetylation of tau protein at lysine 280 may be a critical step in molecular pathology of these neurodegenerative diseases prior to the tau hyperphosphorylation. Secondary injury cascades such as oxidative stress, endoplasmic reticulum stress, and neuroinflammation contribute to lasting damage within the brain and can be induced by a number of different risk factors. These injury cascades funnel into a common pathway of early tau acetylation, which may serve as the catalyst for progressive degeneration. The post translational modification of tau can result in production of toxic oligomers, contributing to reduced solubility as well as aggregation and formation of neurofibrillary tangles, the hallmark of AD pathology. Chronic Traumatic Encephalopathy (CTE), caused by repetitive brain trauma is also associated with a hyperphosphorylation of tau. We postulated acetylation of tau at lysine 280 in CTE disease could be present prior to the hyperphosphorylation and tested this hypothesis in CTE pathologic specimens. We also tested for ac-tau 280 in early stage Alzheimer's disease (Braak stage 1). Histopathological examination using the ac tau 280 antibody was performed in three Alzheimer's cases and three CTE patients. Presence of ac-tau 280 was confirmed in all cases at early sites of disease manifestation. These findings suggest that tau acetylation may precede tau phosphorylation and could be the first "triggering" event leading to neuronal loss. To the best of our knowledge, this is the first study to identify acetylation of the tau protein in CTE. Prevention of tau acetylation could possibly serve as a novel target for stopping neurodegeneration before it fully begins. In this study, we highlight what is known about tau acetylation and neurodegeneration.
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The role of the thymus in long-term immune reconstitution has not been addressed in HIV patients who were severely immunodeficient prior to successful treatment with combination antiretroviral therapy (ART). Adult HIV-1 patients (n = 78) with nadir CD4+ T cell counts <100 T cells/microl, at least 12 months on ART and 6 months of complete viral suppression (<50 HIV RNA copies/ml) were selected from a patient database. The cohort was divided according to current CD4+ T cell counts and patients from the lowest (n = 15) and highest (n = 12) tertiles were studied. Thymic volume was assessed by spiral computed tomography. Naive (CD45RA+CD62L+) and replicating (Ki67+) T cells were quantitated by flow cytometry, T cell receptor excision circles (TREC) were assessed by real-time PCR, and serum IL-7 and testosterone by immunoassay. Patients with low CD4+ T cell counts had smaller thymuses [0(0-5.3) vs. 3.5(0-15.6) cm(3), p = 0.04] and were more likely to have no detectable thymus. They had similar proportions of replicating cells, but fewer naive CD4+ and CD8+ T cells and less TREC in CD4+ and CD8+ T cells/ml of blood than patients with high CD4+ T cell counts. However, some patients with no detectable thymus had high numbers of naive and TREC-bearing T cells. Thus, the recovery of CD4+ T cells in severely immunodeficient HIV patients with a virological response to ART is probably limited by thymic function. However, the data are consistent with extrathymic T cell production contributing to the naive T cell pool in some patients.
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Fármacos Anti-VIH/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , Timo/fisiopatología , Adulto , Anciano , Recuento de Linfocito CD4 , Femenino , Infecciones por VIH/fisiopatología , VIH-1/genética , Humanos , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , ARN Viral , Subgrupos de Linfocitos T , Carga ViralRESUMEN
BACKGROUND: Nonmelanoma skin cancer (NMSC) comprises a heterogeneous group of cancers. A comprehensive review of NMSC mortality has not been performed previously in this region. OBJECTIVE: We sought to document the population affected by lethal NMSC, the types of tumors involved, and their histopathologic features. METHODS: Death certificates of all patients who died from NMSC were examined. Histology of the primary lesion was reviewed in cases when the primary lesion was identified and sections were available. RESULTS: A total of 120 NMSC deaths occurred, including 89 caused by squamous cell carcinoma, 22 by Merkel cell carcinoma, and 9 others. The median age at death was 79 years, unless the patients were immune deficient (68 years). When the primary lesion was identified (n = 45), the median survival after diagnosis was 17 months; 75% of patients died within 3 years. Lethal neoplasms were deeply invasive and infiltrated into the reticular dermis and beyond. Three squamous cell carcinomas were reclassified as adenosquamous carcinoma. CONCLUSION: Lethal NMSC occurs in the elderly and consists mainly of 3 types of deeply invasive cancers.
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Neoplasias Cutáneas/mortalidad , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma Adenoescamoso/mortalidad , Carcinoma Adenoescamoso/patología , Carcinoma de Células de Merkel/mortalidad , Carcinoma de Células de Merkel/patología , Carcinoma de Células Escamosas/mortalidad , Carcinoma de Células Escamosas/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sistema de Registros , Neoplasias Cutáneas/patología , Análisis de Supervivencia , Australia Occidental/epidemiologíaRESUMEN
Ever since the Y2K scare, boards have grown increasingly nervous about corporate dependence on information technology. Since then, computer crashes, denial of service attacks, competitive pressures, and the need to automate compliance with government regulations have heightened board sensitivity to IT risk. Unfortunately, most boards remain largely in the dark when it comes to IT spending and strategy, despite the fact that corporate information assets can account for more than 50% of capital spending. A lack of board oversight for IT activities is dangerous, the authors say. It puts firms at risk in the same way that failing to audit their books would. Companies that have established board-level IT governance committees are better able to control IT project costs and carve out competitive advantage. But there is no one-size-fits-all model for board supervision of a company's IT operations. The correct approach depends on what strategic "mode" a company is in whether its operations are extremely dependent on IT or not, and whether or not it relies heavily on keeping up with the latest technologies. This article spells out the conditions under which boards need to change their level of involvement in IT decisions, explaining how members can recognize their firms' IT risks and decide whether they should pursue more aggressive IT governance. The authors delineate what an IT governance committee should look like in terms of charter, membership, duties, and overall agenda. They also offer recommendations for developing IT policies that take into account an organization's operational and strategic needs and suggest what to do when those needs change. Given the dizzying pace of change in the world of IT, boards can't afford to ignore the state of their IT systems and capabilities. Appropriate board governance can go a long way toward helping a company avoid unnecessary risk and improve its competitive position.
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Comercio/organización & administración , Consejo Directivo , Sistemas de Información , Tecnología , Gastos de Capital , Seguridad Computacional , Toma de Decisiones en la Organización , Falla de Equipo , Humanos , Inversiones en Salud , Estados UnidosRESUMEN
Illness occurring during the initial months of highly active antiretroviral therapy (HAART) for human immunodeficiency virus infection may be a consequence of the restoration of an immune response against opportunistic pathogens (i.e., immune restoration disease [IRD]). We describe a young man who had AIDS complicated by parvovirus B19 infection and RBC aplasia and who developed a painless, progressive dyspraxia of the left arm and an expressive dysphasia 4 weeks after commencing effective HAART. Neuroimaging demonstrated multiple right fronto-parietal lesions, and, following extensive investigations, including a brain biopsy, it was concluded that the brain lesions represented IRD associated with parvovirus B19 infection.
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Terapia Antirretroviral Altamente Activa/efectos adversos , Encefalitis Viral/etiología , Infecciones por VIH/tratamiento farmacológico , Infecciones por Parvoviridae/etiología , Parvovirus B19 Humano , Infecciones Oportunistas Relacionadas con el SIDA/virología , Adulto , Fármacos Anti-VIH/uso terapéutico , Infecciones por VIH/complicaciones , Humanos , Inmunidad , Masculino , Reacción en Cadena de la PolimerasaAsunto(s)
Angioedemas Hereditarios/diagnóstico , Angioedemas Hereditarios/genética , Proteínas Inactivadoras del Complemento 1/genética , Serpinas/genética , Adulto , Secuencia de Aminoácidos , Angioedemas Hereditarios/clasificación , Australia , Secuencia de Bases , Proteína Inhibidora del Complemento C1 , Femenino , Humanos , Datos de Secuencia Molecular , Mutación/genéticaRESUMEN
Peanut allergy is transient in some children but it is not clear whether quantitating peanut-specific IgE by Skin Prick Test (SPT) adds additional information to fluorescent-enzyme immunoassay (FEIA) in discriminating between allergic and tolerant children. To investigate whether SPT with a commercial extract or fresh foods adds additional predictive information for peanut challenge in children with a low FEIA (<10 k UA/L) who were previously sensitized, or allergic to peanuts. Children from a hospital-based allergy service who were previously sensitized or allergic to peanuts were invited to undergo a peanut challenge unless they had a serum peanut-specific IgE>10 k UA/L, a previous severe reaction, or a recent reaction to peanuts (within two years). SPT with a commercial extract, raw and roasted saline soaked peanuts was performed immediately prior to open challenge in hospital with increasing quantity of peanuts until total of 26.7 g of peanut was consumed. A positive challenge consisted of an objective IgE mediated reaction occurring during the observation period. 54 children (median age of 6.3 years) were admitted for a challenge. Nineteen challenges were positive, 27 negative, five were indeterminate and three did not proceed after SPT. Commercial and fresh food extracts provided similar diagnostic information. A wheal diameter of >or=7 mm of the commercial extract predicted an allergic outcome with specificity 97%, positive predictive value 93% and sensitivity 83%. There was a tendency for an increase in SPT wheal since initial diagnosis in children who remained allergic to peanuts while it decreased in those with a negative challenge. The outcome of a peanut challenge in peanut sensitized or previously allergic children with a low FEIA can be predicted by SPT. In this cohort, not challenging children with a SPT wheal of >or=7 mm would have avoided 15 of 18 positive challenges and denied a challenge to one out of 27 tolerant children.
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Inmunoglobulina E/sangre , Hipersensibilidad al Cacahuete/diagnóstico , Hipersensibilidad al Cacahuete/epidemiología , Australia , Niño , Femenino , Humanos , Inmunización , Masculino , Hipersensibilidad al Cacahuete/sangre , Valor Predictivo de las Pruebas , Pruebas CutáneasRESUMEN
The adverse effects of immune activation on CD4(+) T-cell recovery and the relationship between CD4(+) T-cell counts and effector T-cell function were examined in HIV-1 patients receiving long-term effective ART. Patients with nadir CD4(+) T-cell counts <100/microl, > 12 months on ART and >6 months with <50 HIV RNA copies/ml were stratified by current CD4(+) T-cell counts and patients from the lowest (n = 15) and highest (n = 12) tertiles were studied. We assessed proliferation (Ki67), activation (HLA-DR, CD38) and replicative senescence (CD57) by flow cytometry and CD4(+) T-cell responses to CMV by IFN-gamma ELISpot. Proportions of CD4(+) T-cells expressing HLA-DR or CD57 were strong univariate predictors of total (P = 0.0002 and P = 0.002) and naive (P < 0.0001 and P < 0.0001, respectively) CD4(+) T-cell counts, suggesting that CD4(+) T-cell activation drives the depletion of naive CD4(+) T-cells. This was clearest in patients with a small/undetectable thymus. IFN-gamma responses to CMV were similar in patients with low or high CD4(+) T-cell counts.
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Fármacos Anti-VIH/inmunología , Linfocitos T CD4-Positivos/inmunología , Infecciones por VIH/inmunología , Memoria Inmunológica , Activación de Linfocitos , Adulto , Anciano , Fármacos Anti-VIH/uso terapéutico , Biomarcadores/metabolismo , Linfocitos T CD4-Positivos/patología , Proliferación Celular , Femenino , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/patología , Humanos , Masculino , Persona de Mediana Edad , Tamaño de los Órganos , Timo/citología , Timo/inmunología , Timo/patologíaRESUMEN
We investigated whether polymorphisms in genes associated with HIV disease progression and/or immune activation affect CD4+ T-cell recovery in HIV patients who began combination antiretroviral therapy (ART) with advanced immunodeficiency and achieved stable control of plasma viremia. Patients with CD4 T-cell counts <300 cells/microL (n = 33) and >400 cells/microL (n = 37) on ART were compared. A multiple case-control logistic regression associated carriage of BAT1(1,2) or interleukin (IL)6-174(2,2) with low CD4 T-cell counts (P = 0.012). BAT1*2 uniquely marks the central major histocompatibility complex region of a conserved haplotype (HLA-A1,B8,BAT1*2,TNFA-308*2,DR3,DQ2). There was no association between alleles carried at CCR5Delta32, CCR5 59029, CCR5 59353, CCR2+190 (V64I), SDF1 3'UTR, IL1A+4845, IL1B+3953, IL4-589, IL10-592, IL10-R1+536, IL10-R1+1112, IL12B 3'UTR, TNFA-308, or TNFA-1031 and CD4 T-cell counts. We suggest that immune activation and/or CD4 T-cell apoptosis in HIV patients on effective ART is influenced by genetic factors.
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Fármacos Anti-VIH/uso terapéutico , Recuento de Linfocito CD4 , Linfocitos T CD4-Positivos/inmunología , Infecciones por VIH/genética , Infecciones por VIH/inmunología , Interleucina-6/genética , Complejo Mayor de Histocompatibilidad , Polimorfismo Genético , Adulto , Anciano , Secuencia de Bases , Estudios de Casos y Controles , Cartilla de ADN , Femenino , VIH/genética , VIH/aislamiento & purificación , Infecciones por VIH/tratamiento farmacológico , Humanos , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , ARN Viral/sangre , Carga ViralRESUMEN
Susceptibility to a clinically significant drug hypersensitivity syndrome associated with abacavir use seems to have a strong genetic component. We have previously shown that the presence of HLA-B*5701 strongly predicts abacavir hypersensitivity and have identified a potential susceptibility locus within a 300-kb region between the MEGT1 and C4A6 loci in the central MHC. We now report the results of fine recombinant genetic mapping in an expanded patient population of 248 consecutive, fully ascertained, abacavir-exposed individuals in the Western Australian HIV Cohort Study, in which 18 cases of definite abacavir hypersensitivity (7.3%) and 230 tolerant controls were identified. Haplotype mapping within patients with allelic markers of the 57.1 ancestral haplotype suggests a susceptibility locus within the 14-kb Hsp70 gene cluster. HLA-B*5701 was present in 94.4% of hypersensitive cases compared with 1.7% of controls (odds ratio, 960; P < 0.00001). A haplotypic nonsynonymous polymorphism of Hsp70-Hom (HspA1L, resulting from the substitution of residue M493T in the peptide-binding subunit) was found in combination with HLA-B*5701 in 94.4% of hypersensitive cases and 0.4% of controls (odds ratio, 3,893; P < 0.00001). Individuals with abacavir hypersensitivity demonstrated increased monocyte tumor necrosis factor expression in response to ex vivo abacavir stimulation, which was abrogated with CD8(+) T cell depletion. These data indicate that the concurrence of HLA-B*5701 and Hsp70-Hom M493T alleles is necessary for the development of abacavir hypersensitivity, which is likely to be mediated by an HLA-B*5701-restricted immune response to abacavir.