RESUMO
The use of bi-allelic markers such as retrotransposable element insertion polymorphisms or Innuls (for insertion/null) can overcome some limitations of short tandem repeat (STR) loci in typing forensic biological evidence. This study investigated the efficiency of the InnoTyper® 21 Innul markers in an urban admixed population sample in Rio de Janeiro (n = 40) and one highly compromised sample collected as evidence by the Rio de Janeiro police. No significant departures from Hardy-Weinberg equilibrium were detected after the Bonferroni correction (α' ≈ 0.05/20, p < 0.0025), and no significant linkage disequilibrium was observed between markers. Assuming loci independence, the cumulative random match probability (RMP) was 2.3 × 10-8. A lower mean Fis value was obtained for this sample population compared with those of three North American populations (African-American, Southwest Hispanic, US Caucasian). Principal component analysis with the three North American populations and one from 21 East Asian population showed that African Americans segregated as an independent group while US Caucasian, Southwest Hispanic, East Asian, and Rio de Janeiro populations are in a single large heterogeneous group. Also, a full Innuls profile was produced from an evidence sample, despite the DNA being highly degraded. In conclusion, this system is a useful complement to standard STR kits.
Assuntos
Genética Populacional , Retroelementos , Brasil , Impressões Digitais de DNA , Humanos , Polimorfismo Genético , Análise de Componente Principal , Grupos Raciais/genéticaRESUMO
Recent studies have demonstrated that lithium (Li) exerts neuronal protective and regenerative effects both in vitro and in vivo. However, the effects of long-term Li treatment in the brain areas associated with memory impairment of elderly bipolar patients are still unknown. The aim of this study was to compare the hippocampal volumes of elderly bipolar patients using Li, elderly bipolar patients not using Li and healthy controls. Sociodemographic, clinical and magnetic resonance imaging data from 30 elderly euthymic bipolar patients who had been using Li for an average of >61 months; 27 elderly euthymic bipolar patients not taking Li for an average of 45 months; and 22 elderly healthy controls were analyzed. Volumetric differences in the hippocampus between groups were investigated with voxel-based morphometry (VBM) based on the Statistical Parametric Mapping technique. No statistical differences in sociodemographic and clinical characteristics and course of bipolar disorder between the two bipolar groups were observed. Using small volume correction in the VBM analysis (analysis of variance (ANOVA)), one voxel cluster of statistical significance was detected in the left hippocampus (P<0.05 corrected for multiple comparisons, extent threshold >10 voxels). Post hoc unpaired t-tests revealed increased left hippocampal volume in the Li-treated group compared with the non-Li-treated group, and decreased left hippocampal volume in the non-Li group relative to controls. Additional exploratory two-group comparisons indicated trends toward reduced right-hippocampal volumes in the non-Li-treated group relative to both the Li-treated group and controls. The findings suggested that the use of Li may influence the volume of the hippocampus, possibly due to its neuroprotective effects.
Assuntos
Transtorno Bipolar/diagnóstico por imagem , Transtorno Bipolar/tratamento farmacológico , Hipocampo/efeitos dos fármacos , Hipocampo/diagnóstico por imagem , Carbonato de Lítio/efeitos adversos , Carbonato de Lítio/uso terapêutico , Imageamento por Ressonância Magnética , Fármacos Neuroprotetores/efeitos adversos , Fármacos Neuroprotetores/uso terapêutico , Tamanho do Órgão/efeitos dos fármacos , Fatores Etários , Idoso , Estudos de Casos e Controles , Dominância Cerebral/efeitos dos fármacos , Feminino , Humanos , Assistência de Longa Duração , Masculino , Memória/efeitos dos fármacos , Pessoa de Meia-Idade , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/efeitos dos fármacosRESUMO
A newly identified allele of the KIR2DL4 natural killer cell receptor for human leukocyte antigen (HLA) class I.
Assuntos
Alelos , Éxons , Mutação Puntual , Receptores KIR2DL4/genética , Substituição de Aminoácidos , Sequência de Bases , Códon , Haplótipos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Células Matadoras Naturais/citologia , Células Matadoras Naturais/imunologia , Tipagem Molecular , Receptores KIR2DL4/imunologia , Alinhamento de Sequência , Análise de Sequência de DNARESUMO
Killer immunoglobulin-like receptors (KIRs) play an essential role in the regulation of natural killer (NK) activity, allowing NK cells to sense and respond to human leukocyte antigen (HLA) class I downregulation, an important hallmark for viral infections and tumor transformation. KIR and HLA genes are located on different chromosomes and KIR/HLA class I interaction represents an example of genetic epistasis in which the presence of receptor/ligand pairs is necessary for the induction of functional activity, while the presence of one in the absence of the other is not sufficient to influence NK cell function. Due to the high degree of HLA class I and KIR gene variability, KIR/KIR-ligand (KIR-L) interactions are extraordinarily diverse. KIR polymorphism arises from both haplotypic and allelic variations and was shaped by natural selection. KIR variability affects NK cell education influencing the KIR repertoire, KIR expression, the strength of KIR/KIR-L interactions and the capability to deliver signals. Moreover, it may influence NK cell function during infections, autoimmune diseases, pregnancy and allogeneic transplantation. This review summarizes the genetic and functional features of KIR/KIR-L interactions and gives an overview of their potential relevance in clinical studies.
Assuntos
Doenças Autoimunes/imunologia , Antígenos de Histocompatibilidade Classe I/genética , Infecções/imunologia , Células Matadoras Naturais/imunologia , Receptores KIR/genética , Animais , Doenças Autoimunes/genética , Ensaios Clínicos como Assunto , Feminino , Humanos , Infecções/genética , Polimorfismo Genético , Gravidez/imunologia , Transdução de Sinais/genética , Imunologia de Transplantes/imunologiaRESUMO
Endothelial progenitor cells (EPCs) have recently been employed in cell-based therapy (CBT) to promote neovascularization and regeneration of ischemic organs, such as heart and limbs. Furthermore, EPCs may be recruited from bone marrow by growing tumors to drive the angiogenic switch through physical engrafting into the lumen of nascent vessels or paracrine release of pro-angiogenic factors. CBT is hampered by the paucity of EPCs harvested from peripheral blood and suffered from several pitfalls, including the differentiation outcome of transplanted cells and low percentage of engrafted cells. Therefore, CBT will benefit from a better understanding of the signal transduction pathway(s) which govern(s) EPC homing, proliferation and incorporation into injured tissues. At the same time, this information might outline alternative molecular targets to combat tumoral neovascularization. We have recently found that store-operated Ca(2+) entry, a Ca(2+)-permeable membrane pathway that is activated upon depletion of the inositol-1,4,5-trisphosphate-sensitive Ca(2+) pool, is recruited by vascular endothelial growth factor to support proliferation and tubulogenesis in human circulating endothelial colony forming cells (ECFCs). ECFCs are a subgroup of EPCs that circulate in the peripheral blood of adult individuals and are able to proliferate and differentiate into endothelial cells and form capillary networks in vitro and contribute to neovessel formation in vivo. The present review will discuss the relevance of SOCE to ECFC-based cell therapy and will address the pharmacological inhibition of store-dependent Ca(2+) channels as a promising target for anti-angiogenic treatments.
Assuntos
Cálcio/metabolismo , Neoplasias/irrigação sanguínea , Neovascularização Patológica , Células-Tronco/metabolismo , Inibidores da Angiogênese/uso terapêutico , Canais de Cálcio/metabolismo , Sinalização do Cálcio , Terapia Baseada em Transplante de Células e Tecidos , Humanos , Proteínas de Membrana/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias/patologia , Neoplasias/terapia , Proteína ORAI1 , Células-Tronco/citologia , Molécula 1 de Interação EstromalRESUMO
OBJECTIVES: A defined role for natural killer (NK) cells and their activating receptors in autoimmunity has not been clearly established. The aim of this study was to evaluate the levels of the CD3-CD56+ NK cells and their expression of receptors and co-receptors in the peripheral blood of patients with systemic autoimmune disorders. METHODS: Thirty-four subjects with systemic sclerosis (SSc), 14 with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), 14 with systemic lupus erythematosus (SLE), and 14 healthy donors were studied. The activating receptors NKp46, NKp44, NKp30, NKG2D, and DNAM-1 and the co-receptors NTB-A and 2B4 were analysed by flow cytometry on peripheral blood NK cells. RESULTS: In SSc, AAV, and SLE we detected a significant decrease in the percentage of CD3-CD56+ NK cells compared to healthy controls. No differences in the expression of NKp46, NKp44, and NKp30 were identified. On the contrary, NKG2D and DNAM-1 expression was decreased in SLE, but not in SSc and AAV, NTB-A was decreased in SLE, and 2B4 in both SLE and SSc. No differences were detected between active and inactive SLE patients. In SSc, only patients affected by pulmonary arterial hypertension (PAH) and interstitial lung disease (ILD) had a low expression of DNAM-1, 2B4, and NKp30. CONCLUSIONS: These data demonstrate that patients with different systemic autoimmune diseases differ in the expression of activating receptors and co-receptors on CD3-CD56+ NK cells. The down-regulation of receptors and co-receptors in SSc with lung involvement suggests their possible role in this manifestation of the disease.
Assuntos
Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/metabolismo , Células Matadoras Naturais/metabolismo , Lúpus Eritematoso Sistêmico/metabolismo , Receptores de Células Matadoras Naturais/metabolismo , Escleroderma Sistêmico/metabolismo , Adulto , Idoso , Complexo CD3/metabolismo , Antígeno CD56/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
AIMS: To assess whether the expression of B7-H3 surface molecule could improve differential diagnosis of small cell round tumours. METHODS AND RESULTS: One hundred and one well-characterized paraffin-embedded small round cell tumours, stored in the pathology archive of the Gaslini Institute, were immunohistochemically analysed with the 5B14 monoclonal antibody, which recognizes the surface molecule B7-H3. All lymphoblastic lymphomas and the blastematous component of Wilms' tumours were completely negative and a few Ewing's sarcoma and Burkitt's lymphoma specimens showed focal positivity, whereas 74% of neuroblastomas, 67% of rhabdomyosarcomas and 100% of medulloblastomas were positive. The pattern of immunoreactivity of 5B14 mAb observed in rhabdomyosarcoma, neuroblastoma and medulloblastoma specimens was limited to the cytoplasmic membrane, and in neuroblastomas areas of rosette formation or of ganglion differentiation were preferentially stained. Interestingly, in neuroblastoma patients high expression of the antigen recognized by the 5B14 mAb was associated with a worse event-free survival. CONCLUSIONS: The 5B14 mAb represents an additional tool for the differential diagnosis of small round cell tumours and might be useful in identifying neuroblastoma patients at risk of relapse who may take advantage of more careful follow-up.
Assuntos
Antígenos CD/metabolismo , Biomarcadores Tumorais/metabolismo , Neoplasias Encefálicas/metabolismo , Meduloblastoma/metabolismo , Neuroblastoma/metabolismo , Receptores Imunológicos/metabolismo , Rabdomiossarcoma/metabolismo , Antígenos B7 , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/mortalidade , Diagnóstico Diferencial , Humanos , Itália/epidemiologia , Meduloblastoma/diagnóstico , Meduloblastoma/mortalidade , Neuroblastoma/diagnóstico , Neuroblastoma/mortalidade , Prognóstico , Rabdomiossarcoma/diagnóstico , Rabdomiossarcoma/mortalidade , Taxa de SobrevidaRESUMO
Natural killer (NK) cells have been known for many years as the lymphocyte subset characterized by the highest cytolytic potential against virus-infected and tumor-transformed cells. A surprisingly high number of surface molecules have been recognized that regulate human NK cell function. These include MHC-specific inhibitory receptors, which impair NK cells' ability to attack normal self-tissues, and activating receptors and coreceptors that allow them to recognize and kill transformed cells. The recent identification of some of the cellular ligands specifically recognized by these receptors/coreceptors contributes to elucidation of the mystery of the role played by NK cells in immune responses.
Assuntos
Células Matadoras Naturais/imunologia , Neoplasias/imunologia , Receptores Imunológicos/metabolismo , Humanos , Ativação Linfocitária , Modelos ImunológicosRESUMO
Patients with Alzheimer's disease (AD) gradually lose their cognitive competence, particularly memory, and the ability to perform daily life tasks. Neuropsychological rehabilitation is used to improve cognitive functions by facilitating memory performance through the use of external aids and internal strategies. The effect of neuropsychological rehabilitation through memory training - motor movements, verbal association, and categorization - and activities of daily living (ADL) training was tested in a sample of 5 elderly out-patients (mean age: 77.4 +/- 2.88 years), with mild AD (Mini-Mental State Examination score: 22.20 +/- 2.17) and their caregivers. All patients had been taking rivastigmine (6-12 mg/day) for at least 3 months before being assigned to the rehabilitation sessions, and they continued to take the medication during the whole program. Just before and after the 14-week neuropsychological rehabilitation program all patients were assessed by interviewers that did not participate in the cognitive training, using the Mini-Mental State Examination, Montgomery-Alsberg Depression Rating Scale, Hamilton Anxiety Scale, Interview to Determine Deterioration in Functioning in Dementia, Functional Test, Memory Questionnaire of Daily Living for patient and caregiver, Quality of Life Questionnaire for patient and caregiver, and a neuropsychological battery. The results showed a statistically significant improvement in ADL measured by Functional Test (P = 0.04), and only a small improvement in memory and psychiatric symptoms. Our results support the view that weekly stimulation of memory and training of ADL is believed to be of great value in AD treatment, not only delaying the progress of the disease, but also improving some cognitive functions and ADL, even though AD is a progressively degenerative disease.
Assuntos
Atividades Cotidianas , Doença de Alzheimer/reabilitação , Transtornos da Memória/reabilitação , Idoso , Doença de Alzheimer/complicações , Feminino , Humanos , Masculino , Transtornos da Memória/etiologia , Testes Neuropsicológicos , Projetos Piloto , Escalas de Graduação Psiquiátrica , Qualidade de Vida , Reprodutibilidade dos Testes , Índice de Gravidade de DoençaRESUMO
Patients with Alzheimer's disease (AD) gradually lose their cognitive competence, particularly memory, and the ability to perform daily life tasks. Neuropsychological rehabilitation is used to improve cognitive functions by facilitating memory performance through the use of external aids and internal strategies. The effect of neuropsychological rehabilitation through memory training - motor movements, verbal association, and categorization - and activities of daily living (ADL) training was tested in a sample of 5 elderly out-patients (mean age: 77.4 ± 2.88 years), with mild AD (Mini-Mental State Examination score: 22.20 ± 2.17) and their caregivers. All patients had been taking rivastigmine (6-12 mg/day) for at least 3 months before being assigned to the rehabilitation sessions, and they continued to take the medication during the whole program. Just before and after the 14-week neuropsychological rehabilitation program all patients were assessed by interviewers that did not participate in the cognitive training, using the Mini-Mental State Examination, Montgomery-Alsberg Depression Rating Scale, Hamilton Anxiety Scale, Interview to Determine Deterioration in Functioning in Dementia, Functional Test, Memory Questionnaire of Daily Living for patient and caregiver, Quality of Life Questionnaire for patient and caregiver, and a neuropsychological battery. The results showed a statistically significant improvement in ADL measured by Functional Test (P = 0.04), and only a small improvement in memory and psychiatric symptoms. Our results support the view that weekly stimulation of memory and training of ADL is believed to be of great value in AD treatment, not only delaying the progress of the disease, but also improving some cognitive functions and ADL, even though AD is a progressively degenerative disease.
Assuntos
Humanos , Masculino , Feminino , Idoso , Atividades Cotidianas , Doença de Alzheimer/reabilitação , Transtornos da Memória/reabilitação , Doença de Alzheimer/complicações , Transtornos da Memória/etiologia , Testes Neuropsicológicos , Projetos Piloto , Escalas de Graduação Psiquiátrica , Qualidade de Vida , Reprodutibilidade dos Testes , Índice de Gravidade de DoençaRESUMO
Phospholipase A(2) (PLA(2)) controls the metabolism of phospholipids in cell membranes. In the brain, PLA(2) influences the processing of the amyloid precursor protein (APP) and thus the production of the amyloid-beta peptides (Abeta), which are the major components of the senile plaques in Alzheimer's disease (AD). Reduced PLA(2) activity has been reported in brain and in platelets of AD patients. In the present study we investigated PLA(2) activity in platelets from 21 AD patients as compared to 17 healthy elderly controls and 11 individuals with mild cognitive impairment (MCI). Subjects were cognitively assessed by the Mini-Mental State Examination (MMSE) and the CAMDEX schedule. Platelet PLA(2) activity was determined by radio-enzymatic assay, which mainly detected a calcium-independent form of the enzyme present also in the brain (iPLA(2)). PLA(2) activity was significantly lower in AD than in controls (p < 0.001). Mean PLA(2) activity in MCI individuals was between the values of AD patients and controls, with a subgroup showing PLA as low as the lowest AD patients, but the differences from MCI were not significant from AD and control groups. Lower PLA(2) activity was significantly correlated with a worse cognitive performance both at the MMSE (p = 0.001) and the cognitive sub-scale of the CAMDEX inventory (p = 0.002). Our data replicate previous findings of reduced platelet PLA(2) activity in AD. Both reduced PLA(2) activity and the correlation with impaired cognition were also reported in brain tissue of AD patients, suggesting thus that the present determinations in platelets may be related to a reduction in the brain. In the brain the inhibition of PLA(2) inhibits the physiological secretion of the APP, a mechanism that increases Abeta formation. Further longitudinal studies should investigate whether those MCI individuals with the lowest PLA(2) values in platelets would be at a higher risk to develop AD during a longitudinal follow up.
Assuntos
Doença de Alzheimer/enzimologia , Plaquetas/enzimologia , Transtornos Cognitivos/enzimologia , Fosfolipases A/metabolismo , Idoso , Doença de Alzheimer/sangue , Biomarcadores/sangue , Transtornos Cognitivos/sangue , Feminino , Humanos , Masculino , Testes NeuropsicológicosRESUMO
The past 10years have witnessed dramatic progress in our understanding of how natural killer (NK) cells function and their role in innate immunity. Thanks to an array of inhibitory receptors specific for different HLA class I molecules, human NK cells can sense the decrease or loss of even single alleles at the cell surface. This represents a typical condition of a potential danger, i.e. the presence of tumor or virally infected cells. NK cell triggering and lysis of these cells is mediated by several activating receptors and coreceptors that have recently been identified and cloned. While normal cells are usually resistant to NK-mediated attack, a remarkable exception is represented by dendritic cells (DCs). In their immature form they are susceptible to NK-mediated lysis because of the expression of low levels of surface HLA class I molecules. The process of DC maturation (mDCs) is characterized by the surface expression of high levels of HLA class I molecules. Accordingly, mDCs become resistant to NK cells. A recent major breakthrough highlighted the role played by donor NK cells in allogenic bone marrow transplantation to cure acute myeloid leukemias. 'Alloreactive' NK cells derived from donor hematopoietic precursors not only prevented leukemic relapses, but also prevented graft rejection and graft-versus-host disease.
Assuntos
Células Dendríticas/fisiologia , Células Matadoras Naturais/fisiologia , Receptores de Superfície Celular/fisiologia , Humanos , Células Matadoras Naturais/imunologia , Transplante de Células-TroncoRESUMO
OBJECTIVE: To investigate the relation between atrophy of the hippocampal region and brain functional patterns during episodic memory processing in Alzheimer's disease. PATIENTS AND METHODS: Whole brain structural magnetic resonance imaging (MRI) data and single photon emission computed tomography (SPECT) measures of regional cerebral blood flow (rCBF) were obtained during a verbal recognition memory task in nine subjects with mild Alzheimer's disease and 10 elderly healthy controls. Using the statistical parametric mapping approach, voxel based comparisons were made on the MRI data to identify clusters of significantly reduced grey matter concentrations in the hippocampal region in the Alzheimer patients relative to the controls. The mean grey matter density in the voxel cluster of greatest hippocampal atrophy was extracted for each Alzheimer subject. This measure was used to investigate, on a voxel by voxel basis, the presence of significant correlations between the degree of hippocampal atrophy and the rCBF SPECT measures obtained during the memory task. RESULTS: Direct correlations were detected between the hippocampal grey matter density and rCBF values in voxel clusters located bilaterally in the temporal neocortex, in the left medial temporal region, and in the left posterior cingulate cortex during the memory task in the Alzheimer's disease group (p < 0.001). Conversely, measures of hippocampal atrophy were negatively correlated with rCBF values in voxel clusters located in the frontal lobes, involving the right and left inferior frontal gyri and the insula (p < 0.001). CONCLUSIONS: Hippocampal atrophic changes in Alzheimer's disease are associated with reduced functional activity in limbic and associative temporal regions during episodic memory processing, but with increased activity in frontal areas, possibly on a compensatory basis.
Assuntos
Doença de Alzheimer/diagnóstico , Doença de Alzheimer/fisiopatologia , Encéfalo/irrigação sanguínea , Encéfalo/fisiopatologia , Imageamento por Ressonância Magnética , Transtornos da Memória/diagnóstico , Lobo Temporal/irrigação sanguínea , Lobo Temporal/patologia , Tomografia Computadorizada de Emissão de Fóton Único , Atrofia/patologia , Circulação Cerebrovascular/fisiologia , Feminino , Hipocampo/irrigação sanguínea , Hipocampo/patologia , Humanos , Masculino , Testes Neuropsicológicos , Índice de Gravidade de Doença , Fatores SexuaisRESUMO
Recent years have witnessed remarkable progress in our understanding of the molecular mechanism regulating natural killer (NK) cell function. NK cells can sense whether cells have lost the surface expression of major histocompatibility complex (MHC)-class I molecules. The discovery of MHC-class I-specific inhibitory receptors clarified the basis of this discrimination and elucidated the nature of the 'off' signal. However, the receptors responsible for the 'on' signal in the process of natural cytotoxicity remained mysterious until recently. Here, we describe the identification and characterization of such receptors and discuss the emerging implications of these findings in different diseases.
Assuntos
Células Matadoras Naturais/imunologia , Alergia e Imunologia , Animais , Distinções e Prêmios , Citotoxicidade Imunológica , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Imunidade Inata , Transtornos Linfoproliferativos/genética , Transtornos Linfoproliferativos/imunologia , Neoplasias/imunologia , Receptores Imunológicos/metabolismo , SuéciaRESUMO
BACKGROUND: Behavioral and psychological symptoms in dementia (BPSD) contribute to caregiver burden and institutionalization of elderly. Neuroleptics are prescribed to control agitation. Side effects of typical neuroleptics are harmful, making atypical neuroleptics an indication. OBJECTIVES: To evaluate efficacy and tolerability of risperidone oral solution (ROS) given once daily to demented elderly outpatients with BPSD (agitation). METHOD: Patients (n=26), 76.35+/-8.63 years, Diagnostic and Statistical Manual of Mental Disorders 4th ed. (DSM-IV) criteria for dementia. RSO was given, starting dose of 0.25 mg and increments of 0.25 mg every week. Mini-Mental State Examination (MMSE) assessed cognitive status, Behavioral and Emotional Activities Manifested in Dementia (BEAM-D) and Clinical Global Impression (CGI) measured BPSD, Extrapiramidal Symptom Rating Scale (ESRS) evaluated extrapyramidal symptoms. Cardiovascular side effects were evaluated clinically. RESULTS: There was a 26% reduction in agitation and no cardiovascular side effects in the range from 1.0 to 1.25 mg. Side effects were more prevalent above 2.5 mg. CONCLUSION: Risperidone oral solution improved agitation with good tolerability from 0.5 to 1.25 mg. A single dose with increments of 0.25 mg may be more acceptable to patients and caregivers.
Assuntos
Antipsicóticos/administração & dosagem , Demência/complicações , Agitação Psicomotora/tratamento farmacológico , Risperidona/administração & dosagem , Administração Oral , Idoso , Doença de Alzheimer/complicações , Doença de Alzheimer/psicologia , Doenças dos Gânglios da Base/psicologia , Demência/psicologia , Demência Vascular/complicações , Demência Vascular/psicologia , Emoções , Feminino , Humanos , Institucionalização , Masculino , Escalas de Graduação Psiquiátrica , Resultado do TratamentoRESUMO
Recent years have witnessed major progress in our understanding of the molecular mechanisms regulating natural killer cell (NK cell) function. These advances stem primarily from the discovery of a number of receptors specific for major histocompatibility complex (MHC) class I and, more recently, of the activating receptors and coreceptors responsible for natural cytotoxicity. Important studies performed over the past year have allowed us to define the evolution of the MHC-specific inhibitory receptors by comparative analysis in different species. The roles of the 'activating natural cytotoxicity receptors', NKG2D and certain coreceptors in the lysis of different tumors have been defined in detail. The mechanism by which the 2B4 coreceptor renders patients with X-linked lymphoproliferative disease unable to control Epstein-Barr virus has been elucidated. Inhibitory receptors identified in NK cells may also be expressed by normal and leukemic myeloid cells, in which they can block cell proliferation and survival. It has also become clear that viruses such as cytomegalovirus have evolved strategies to interfere with NK-cell function to protect themselves from NK-mediated attack.
Assuntos
Células Matadoras Naturais/efeitos dos fármacos , Receptores Imunológicos/efeitos dos fármacos , Citotoxicidade Imunológica , Antígenos HLA/efeitos dos fármacos , Humanos , Receptores Imunológicos/antagonistas & inibidoresRESUMO
Previous studies reported that depressed subjects had more signal hyperintensities on magnetic resonance imaging scans than control subjects, but the subjects had cerebrovascular disease risk factors. This study used subjects with a history of major depression and matched comparison subjects, screened to exclude cerebrovascular risk factors, to determine whether depressed subjects had more white matter hyperintensities and other lesions. We evaluated the prevalence and severity of MRI signal hyperintensities in 30 elderly depressed patients and 20 controls matched for age. Deep matter hyperintensities, periventricular hyperintensities and subcortical gray hyperintensities were rated on a standard 0-3 scale by two radiologists blind to clinical diagnosis. No significant differences were found between groups for the presence of subcortical gray matter, deep white matter and periventricular hyperintensities. These findings suggest that cerebrovascular disease risk factors most likely mediated the relationship between depression and hyperintensities in previous studies.
Assuntos
Encéfalo/fisiopatologia , Transtorno Depressivo/fisiopatologia , Imageamento por Ressonância Magnética , Idoso , Idoso de 80 Anos ou mais , Arteriosclerose/complicações , Encéfalo/patologia , Estudos de Casos e Controles , Córtex Cerebral/anatomia & histologia , Córtex Cerebral/patologia , Transtornos Cerebrovasculares/etiologia , Transtorno Depressivo/diagnóstico , Complicações do Diabetes , Feminino , Humanos , Hiperlipidemias/complicações , Hipertensão/complicações , Masculino , Pessoa de Meia-Idade , Fatores de RiscoRESUMO
In humans, natural killer (NK) cell function is regulated by a series of receptors and coreceptors with either triggering or inhibitory activity. Here we describe a novel 60-kD glycoprotein, termed NTB-A, that is expressed by all human NK, T, and B lymphocytes. Monoclonal antibody (mAb)-mediated cross-linking of NTB-A results in the induction of NK-mediated cytotoxicity. Similar to 2B4 (CD244) functioning as a coreceptor in the NK cell activation, NTB-A also triggers cytolytic activity only in NK cells expressing high surface densities of natural cytotoxicity receptors. This suggests that also NTB-A may function as a coreceptor in the process of NK cell activation. Molecular cloning of the cDNA coding for NTB-A molecule revealed a novel member of the immunoglobulin superfamily belonging to the CD2 subfamily. NTB-A is characterized, in its extracellular portion, by a distal V-type and a proximal C2-type domain and by a cytoplasmic portion containing three tyrosine-based motifs. NTB-A undergoes tyrosine phosphorylation and associates with the Src homology 2 domain-containing protein (SH2D1A) as well as with SH2 domain-containing phosphatases (SHPs). Importantly, analysis of NK cells derived from patients with X-linked lymphoproliferative disease (XLP) showed that the lack of SH2D1A protein profoundly affects the function not only of 2B4 but also of NTB-A. Thus, in XLP-NK cells, NTB-A mediates inhibitory rather than activating signals. These inhibitory signals are induced by the interaction of NTB-A with still undefined ligands expressed on Epstein-Barr virus (EBV)-infected target cells. Moreover, mAb-mediated masking of NTB-A can partially revert this inhibitory effect while a maximal recovery of target cell lysis can be obtained when both 2B4 and NTB-A are simultaneously masked. Thus, the altered function of NTB-A appears to play an important role in the inability of XLP-NK cells to kill EBV-infected target cells.
Assuntos
Linfócitos B/imunologia , Linfócitos B/virologia , Herpesvirus Humano 4/imunologia , Células Matadoras Naturais/imunologia , Transtornos Linfoproliferativos/imunologia , Glicoproteínas de Membrana/imunologia , Animais , Anticorpos Monoclonais , Sequência de Bases , Citotoxicidade Imunológica , Primers do DNA/genética , Humanos , Técnicas In Vitro , Transtornos Linfoproliferativos/genética , Masculino , Glicoproteínas de Membrana/química , Glicoproteínas de Membrana/genética , Camundongos , Mutação , Receptores Imunológicos/química , Receptores Imunológicos/genética , Domínios de Homologia de srcRESUMO
In the absence of sufficient signaling by their HLA class I-specific inhibitory receptors, human natural killer (NK) cells become activated and display potent cytotoxicity against cells that are either HLA class I negative or deficient. This indicates that the NK receptors responsible for the induction of cytotoxicity recognize ligands on target cells different from HLA class I molecules. On this basis, the process of NK-cell triggering can be considered as a mainly non-MHC-restricted mechanism. The recent identification of a group of NK-specific triggering surface molecules has allowed a first series of pioneering studies on the functional/molecular characteristics of such receptors. The first three members of a receptor family that has been termed natural cytotoxicity receptors (NCR) are represented by NKp46, NKp44 and NKp30. These receptors are strictly confined to NK cells, and their engagement induces a strong activation of NK-mediated cytolysis. A direct correlation exists between the surface density of NCR and the ability of NK cells to kill various target cells. Importantly, mAb-mediated blocking of these receptors has been shown to suppress cytotoxicity against most NK-susceptible target cells. However, the process of NK-cell triggering during target cell lysis may also depend on the concerted action of NCR and other triggering receptors, such as NKG2D, or surface molecules, including 2B4 and NKp80, that appear to function as co-receptors rather than as true receptors. Notably, a dysfunction of 2B4 has been associated with a severe form of immunodeficiency termed X-linked lymphoproliferative disease. Future studies will clarify whether also the altered expression and/or function of other NK-triggering molecules may represent a possible cause of immunological disorders.