Alterações fenotipicas e transcricionais em linfócitos T de uma população idosa em risco imune no sul do Brasil

Abstract

The elderly population, characterized as people over 60 years old, has grown rapidly in recent years in Brazil, and with this increase in life expectancy, age-related changes appear, for example, immunosenescence. Some studies have shown that there are differences in the immunological profile of the elderly, often related to the numbers of T cells. The immune risk profile (IRP) has been defined as CD4/CD8 T-cell ratio <1 and positivity for serum anti-cytomegalovirus (CMV) antibodies. In this study, we investigated patterns of activation and differentiation of T lymphocytes by flow cytometry in an elderly population in IRP, compared with elderly people without risk profile (non-IRP), seeking to identify additional markers for this risk profile immune. For this study we recruited 60 elderly SUS patients in Porto Alegre, aged 60 years, 30 IRP and 30 non-IRP. Lymphocytes were isolated and stimulated in vitro to evaluate the production of cytokines and the expression of transcription factors. The subpopulations of T lymphocytes found were consistent with previous studies in which IRP patients had fewer naive and central memory T cells, as well as an increase was observed in the percentage of T cells CD8 + CD28-T cells and CD8 + PD-1 + in the IRP individuals. Furthermore, there was a reduction in mean fluorescence intensity (MFI) of transcription factors to canonical subtypes of T cell help (CD4 +) in IRP patients when compared to patients without IRP. The percentages of the different subtypes (TH1, TH2, TH17; Treg) of these cells were not different between the two groups. After stimulation with anti-CD3/anti-CD28 antibodies in culture for 24 hours, the concentration of cytokines in culture supernatants increased, but no significant differences between the two groups were found, except for IL-10, which was higher in IRP patients before stimulation. These results suggested that transcriptional mechanisms important in the differentiation of helper T cells are altered in IRP patients, which may affect the immune response of these individuals.