Is thymus redundant after adulthood?
Thymus is considered to involute with age with a decline in thymic function. However, this generality is not universally and incontrovertibly true. Many studies performed in animals and men have proved to the contrary that thymic activity and function appear to be well maintained in the old age and may be indispensable for T cell reconstitution in different immunological settings. During some clinical situations where T cell pool needs to be regenerated, renewal of thymic activity and mass has been observed in an otherwise dormant thymic remnant. New studies have revealed a dynamic interplay between postnatal thymus output and peripheral T cell pool. Moreover, age-related loss of thymic function appears to be only quantitative and not qualitative. This review, thus, focuses on the different conditions that lead to thymic involution and attempts to bring about the emerging notion and the clinical relevance of continuous thymic activity well beyond the adulthood to optimise the function of the immune system in the context of cancer and infectious diseases.
Shanker
Anil
A
Centre d'Immunologie de Marseille-Luminy, Institut National de la Santé et de la Recherche Médicale, Université de la Méditerranée, 163 Avenue de Luminy, Case 906, Marseille Cedex 09, 13288 France. shankera@ncifcrf.gov
D000375:Aging / Q000276:immunology*; D000818:Animals; D001284:Atrophy; D006801:Humans; D009369:Neoplasms / Q000276:immunology / Q000473:pathology; D013312:Stress, Physiological; D013601:T-Lymphocytes / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology* / Q000473:pathology