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Mediators of Inflammation
Volume 2005 (2005), Issue 4, Pages 245-247
http://dx.doi.org/10.1155/MI.2005.245

Age-Related Modifications in Circulating IL-15 Levels in Humans

1Department of Human Pathology, School of Allergy and Clinical Immunology, University of Messina, Messina 98125, Italy
2Department of Internal Medicine, Division of Geriatric Medicine, University of Messina, Messina 98125, Italy
3Department of Experimental Oncological Pathology, University of Florence, Tuscany, 50134, Italy
4Department of Internal Medicine, University of Messina, Messina 98125, Italy
5Interdepartmental Center “L. Galvani” for Integrated Studies on Bioinformatics, Biophysics, and Biocomplexity, University of Bologna, Bologna 40100, Italy

Received 25 February 2005; Accepted 18 April 2005

Copyright © 2005 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Aging is associated to a progressive establishing of a chronic inflammatory state linked to a continuous long exposure to antigens. Since IL-15 stimulates the proliferation of memory T cells and the immunosenescence is characterized by accumulation of memory T cells and exhaustion of naive T cells, we analyzed IL-15 levels in sera from 30 ultralongeval subjects with respect to those from young and old adults. IL-15 levels were assayed by immunoenzymatic methods. Ultralongeval subjects displayed significantly higher IL-15 levels with respect to both young and old controls. No statistical difference was found between old and young controls. These findings may explain, at least in part, the characteristic increase of memory cells in immunosenescence and the capacity of the immune system of centenarians to defend itself from infections through immune-inflammatory responses.