Sepsis and Immunosenescence in the Elderly Patient: A Review

Abstract

Sepsis is a prevalent, serious medical condition with substantial mortality and a significant consumption of health-care resources. Its incidence has increased around 9% annually in general population over the last years and specially in aged patients group. Several risk factors such as comorbidities, preadmission status, malnutrition, frailty, and an impared function in the immune system called immunosenescence are involved in the higher predisposition to sepsis in the elderly patients. Immunosenescence status consists in a functional impairment in both cell-mediated immunity and humoral immune responses and increases not only the risk for develop sepsis but also lead to more severe presentation of infection and may be is also related with a higher mortality. There is a also a concern about to admit patients in the intensive care units taking into account that the outcome of elderly patients is poorer compared to younger people. Nevertheless, the management of septic elderly patients does not differ substantially from younger people. In addition, the quality of life in septic elderly survivors is also lower than in younger people. But age, as alone factor, should not be used to determine treatment options because the poorer outcomes is thought to be due to the increased comorbidities and frailty in this group of patients.

Keywords: elderly patients; immunosenescence; outcome; quality of life; sepsis.

Figure 1

Invading pathogens induce innate immune responses at the infection point. The pathogen agent is taken up by macrophages and dendritic cells (DCs). Macrophages present the antigen to the lymph nodes in major histocompatibility complex class II (MHC class II) molecules associated to the secretion of proinflammatory cytokines. On the other side, mature DCs migrate to the lymph node and present both MHC class I and II molecules. Infected cells are eliminated by natural killer (NK) cells [modified from Ref. (15), with permission of John Wiley and Sons].

Figure 2

Macrophages and dendritic cells (DCs) activate a clonal expansion of naïve CD4+ and CD8+ T-cell. CD4+ T-cell help and the antigen induce the differentiation of naïve B-cells, then into memory B-cells and antibody-secreting cells. Long-term immunity in the blood and lymph nodes is related to T-cells and B-cells [modified from Ref. (15), with permission of John Wiley and Sons].