Introduzione o prefazione

The ageing of the immune system, immunosenescence, is associated with important remodelling changes in all lymphoid organs and its cells. However, the pace of ageing differs between people with the same chronological age, indicating that it may be thus influenced by extrinsic factors, including the chronic stress. In fact, young adults under chronic psychosocial stress may present immunosenescence features similarly to those found in older adults. Immunosenescence contributes to the onset and clinical course of age-related diseases such as neurodegenerative disorders, cancer, rheumatoid arthritis, cardiovascular and metabolic diseases. This article reviews that premature immunosenescence is observed in adults under chronic psychological stress as well as in healthy adolescents with history of childhood maltreatment. Superimposing stress during ageing is associated with further decline in adaptive immunity, increased inflammaging, accelerated cellular senescence and increased susceptibility to infections. This is of great interest for the COVID-19 pandemic, making the chronically stressed older adults of particular risk for worsen disease outcomes and poor vaccine responses.