title: Immunosenescence: Implications for response to infection and vaccination in older people.
abstract: People aged 60 and older represent over 11% of the world population and it is expected to rise 22% by 2050. Population aging is associated to an increased frequency of age-related diseases including higher susceptibility to infections, cancer, cardiovascular and neurodegenerative diseases. Immunosenescence refers to the decline of the immune system associated to aging. It affects both, innate and adaptive immunity limiting the response to pathogens and to vaccines. The analyses of the immune system in elderly individuals determined several immune signatures constituting an immune risk phenotype that predicts mortality. An inverse CD4/CD8 ratio, loss of naïve T cells, increased numbers of terminally-differentiated T cells and oligoclonal expansions of virus-specific T cells constitute hallmarks of immunosenescence. Natural killer (NK) cells are also found severely altered in the elderly. The contribution of latent cytomegalovirus infection to immunosenescence of T and NK cells has been shown. Considering the worldwide ageing of the population in the next decades, the impact of infections will be a real health problem for older individuals requiring preventive strategies. Thus, further studies are required to analyse the bases of immunosenescence and to establish protocols to overcome the age-associated alterations of the immune response in order to define effective vaccines against those pathogens, such as influenza, contributing to increased morbidity and mortality in the elderly.
authors.affiliation: Department of Immunology, IMIBIC, Reina Sofia University Hospital, University of Cordoba, REIPI, Cordoba, Spain.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Pera
authors.affiliation: Department of Immunology, IMIBIC, Reina Sofia University Hospital, University of Cordoba, REIPI, Cordoba, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Campos
authors.affiliation: Department of Immunology, IMIBIC, Reina Sofia University Hospital, University of Cordoba, REIPI, Cordoba, Spain.
authors.forename: Nelson
authors.initials: N
authors.lastname: López
authors.affiliation: Department of Immunology, IMIBIC, Reina Sofia University Hospital, University of Cordoba, REIPI, Cordoba, Spain.
authors.forename: Fakhri
authors.initials: F
authors.lastname: Hassouneh
authors.affiliation: Department of Immunology, IMIBIC, Reina Sofia University Hospital, University of Cordoba, REIPI, Cordoba, Spain.
authors.forename: Corona
authors.initials: C
authors.lastname: Alonso
authors.affiliation: Immunology Unit, University of Extremadura, Caceres, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Tarazona
authors.affiliation: Department of Immunology, IMIBIC, Reina Sofia University Hospital, University of Cordoba, REIPI, Cordoba, Spain. Electronic address: rsolana@uco.es.
authors.forename: Rafael
authors.initials: R
authors.lastname: Solana
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology*; D003586:Cytomegalovirus Infections / Q000276:immunology*; D004198:Disease Susceptibility; D005260:Female; D006801:Humans; D000068884:Immunosenescence / Q000502:physiology*; D008297:Male; D013601:T-Lymphocytes / Q000276:immunology; D014611:Vaccination
keywords: CMV; Immunosenescence; Influenza; NK cells; T cells; Vaccination