[Immunosenescence: a review]

Immunosenescence is a progressive deterioration of the immune system with ageing. A multifactorial condition, including multimorbidities and environmental factors in the elderly, increases the frailty risks. Some infection and nutritional factors contribute to the onset of decline of response to infection. The epithelial barrier is the front line against infection. The renewal capacity of hematopoietic stem cells is reduced and provide in turn decrease of immune cells like lymphocytes, antigen-presenting dendritic cells, and phagocytes. The cellular immunity decreases considering the low cytotoxicity of natural killer. The impairment of dendritic cells alters both non-adaptive and humoral immunities. The reduction of antibody producing B-cells alters humoral production and the diversity of immunoglobulins and their affinity. Somme evidence suggests that retained function of both innate and acquired immunity in the elderly is correlated with health status. CMV might play a part in the process of immunosenescence. CMV status is included in the immune risk profile. Some factors like nutritional status and inflammatory biomarkers should be added to define a immune risk profile in the elderly.