BackgroundAging is accompanied by alterations in immune response which leads to increased susceptibility to infectious diseases, cancer, autoimmunity, and inflammatory disorders. This decline in immune function is termed as immunosenescence; however, the mechanisms are not fully elucidated. Experimental approaches of adaptive immunity, particularly for T cells, have been the main focus of immunosenescence research. This systematic review evaluates and discusses T cell markers implicated in immunosenescence.ObjectiveTo determine the best flow cytometry markers of circulating T cells associated with immunosenescence.MethodsWe systematically queried PubMed, MEDLINE, EBSCO, and BVS databases for original articles focused on two age groups of healthy humans: 18–44 (young adults) and >60 (older adults) years. In accordance with the Cochrane methodology, we synthesized data through qualitative descriptions and quantitative random effects meta-analysis due to extensive heterogeneity.ResultsA total of 36 studies conducted in the last 20 years were included for the qualitative analysis and four out of these studies were used to perform the meta-analysis. A significant decrease in naïve T cell subset was observed in older adults compared to young adults. Primary markers used to identify senescent cells were loss of CD28 and increased expression of CD57 and KLRG1 in terminally-differentiated memory T cell subset in older adults. Moreover, we observed an increase in proinflammatory cytokines and decrease in telomere length in old adult T cells. It was not possible to perform quantitative synthesis on cell markers, cytokines, and telomere length because of the significant variations between the groups, which is attributed to differences in protocols and unreported measurements, thus generating a high risk of bias.ConclusionsHeterogeneity among studies in terms of data report, measurement techniques and high risk of bias were major impediments for performing a robust statistical analysis that could aid the identification of eligible flow cytometry markers of immunosenescence phenotype in T cells.
Breast cancer is the leading cause of cancer deaths in women worldwide. It has been observed that the incidence of breast cancer increases linearly with age after 45, which suggest a link between cancer, aging, and senescence. A growing body of evidence indicates that the immunosuppressive tumor network in breast cancer patients can lead to T-cell exhaustion and senescence. Cytotoxic chemotherapy is a common treatment for many cancers, and it is hypothesized that its efficacy may be related to immune activation. However, the effects of neoadjuvant chemotherapy on T-cell dysfunction in breast cancer patients are not fully understood. This study aimed to evaluate the impact of neoadjuvant chemotherapy on the expression of exhaustion and senescence markers in T cells in women with breast cancer. Our results showed that T cells from breast cancer patients have a reduced ability to respond to stimulation in-vitro and an increased expression of senescence and exhaustion-associated markers, such as TIM-3, LAG3, and CD57. Furthermore, we found that neoadjuvant chemotherapy has an immunomodulatory effect and reduces the expression of exhaustion markers. Our observations of the immune phenotype of T cells during neoadjuvant chemotherapy treatment highlight its ability to stimulate the immune system against cancer. Therefore, monitoring the response of T cells during chemotherapy may enable early prediction of clinical response.
Estadístico de raíz unitaria con cambio estructural para el impuesto de renta Cuadro 6.5 Estadístico de Bai-Perron para múltiples rupturas estructurales del lnPIB 1920-2019 .
Monitoring literature on the broad spectrum of the human immune response to SARS-CoV-2 is important to understand the mechanisms and progression of COVID-19. The present study undertakes a scoping review of the literature on human immune response to SARS-CoV-2 to determine the characteristics of innate and adaptive responses, as well as biomarkers and cells that play a role in the development of the infection. We searched papers in MEDLINE/PUBMED and EMBASE databases published since December 1st 2019 to to April 9th 2020 from which we selected 56 for this study. We found that the immune response is characterized by high levels of acute phase reactants, neutrophilia, low levels of NKs and eosinophils, lymphopenia, cytokine storm syndrome, exhausted T cells, impaired cytotoxic response, inadequate helper response and production of specific antibodies; concluding that immune dysregulation correlates with disease severity and high mortality.Respuesta inmune humana al SARS-CoV-2: ¿Qué se conoce? Una scoping review.
ResumenEl seguimiento de la literatura sobre la respuesta inmune humana al SARS-CoV-2 es importante para comprender los mecanismos y la progresión de COVID-19. En el presente estudio se realizó un Scoping Review de la literatura sobre la respuesta inmune humana al SARS-CoV-2 para determinar las características de la respuesta inmune innata y adaptativa, así como biomarcadores y células que juegan un papel en el desarrollo de la infección. Buscamos artículos en las bases de datos MEDLINE / PUBMED y EMBASE publicados desde el 1 de diciembre de 2019 hasta el 9 de abril de 2020, de los cuales seleccionamos 56 publicaciones para este estudio. Encontramos que la respuesta inmune se caracteriza por altos niveles de reactantes de fase aguda, neutrofilia, bajos niveles de NKs y eosinófilos, linfopenia, síndrome de tormenta de citoquinas, linfocitos T agotados, respuesta citotóxica alterada, respuesta T helper inadecuada y producción de anticuerpos específicos. En conclusión, el desequilibrio inmune se correlaciona con la severidad y la mortalidad de la enfermedad.
Bone scintigraphy is an extremely valuable technique in diagnosis and treatment planning for patients with condylar hyperplasia (CH). The main objective of this study was to develop an approach to determine normal activity values in the mandibular condyles, adjusted to age and sex, through quantitative analysis of bone single-photon emission computed tomography (SPECT) on a condyle-by-condyle basis and to compare these values with those of a control group comprising patients with confirmed CH. Technetium 99 m-methylene diphosphonate ( 99m Tc-MDP) SPECT studies of the mandibular condyles were performed in patients with no mandibular pathology for quantitative analysis. Regions of interest were drawn on slices representing the upper, middle, and inferior thirds of each condyle and on the summation of transaxial slices representing the whole condyle (three-dimensional approach). The clivus was used for internal validation and the condyle to clivus ratios were calculated. These ratios were compared between 'normal' and 'diseased' condyles. A total 144 condyles in normal patients and 25 in confirmed CH patients were analysed. Differences between the ratios were evaluated through the coefficient of variation. In normal patients, the ratios to the clivus on the summed condyle image showed the lowest variability: range 0.3-1.28 (median 0.74). The quantile regression model showed significant differences with respect to sex, but not to age. The Mann-Whitney test showed significant differences in the ratios to clivus between normal and diseased condyles (P < 0.0001).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.