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Indexed/Abstracted in: EMBASE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 0,246
Department of General Medicine and Therapy, University of Parma, Italy
It is generally believed that the immune function progressively deteriorates with age. However, by selecting healthy subjects by a strict protocol (SENIEUR), several immune defects were not detectable with age. In this regard, the study of several immune parameters revealed significant changes in the T cell subsets accompanied by an increase of cells with NK markers and a significant decrease of B cells. At the functional level, natural killer and anti-CD16 redirected killing activities of extremely old subjects were comparable to those of young controls, while middle-aged subjects showed, surprisingly, a significant reduction of unknown origin. An important and extensively studied immune function is lymphocyte capability to proliferate. By using several mitogens including membrane and transmembrane stimuli a “complex pattern” of lymphocyte proliferative capability emerges. In particular, by using some stimuli (PHA, rIL2 or MLRs) a progressive age-dependent decline in the lymphocyte proliferative response occurs. However, by using more clearly defined stimuli (anti-CD3 mAb or PMA) no differences in the proliferative capability between centenarians, middle-aged and young subjects are observed. Furthermore, the study of the main costimulatory pathway, via CD28 molecule, function well during the aging process including centenarians. Thus, several important activation pathways are well preserved with age. Regarding humoral immunity, it was observed that organ-specific auto-antibodies (anti-Thyroglobulin, anti-peroxidase) progressively increase with age but are virtually absent in centenarians. However, it has subsequently been shown that organ-specific auto-antibodies were also absent in healthy old subjects. Moreover, serum IgG and IgA were significantly raised with age while IgM remained unchanged. In contrast with the increase of Ig, we observed a progressive reduction of circulating B cells including B cells expressing CD5 molecule (a subset able to secrete poly-reactive auto-antibodies). In conclusion, careful studies of healthy humans from newborns to centenarians suggest that a continuous “remodeling” occurs with age. Indeed, the aging process is not associated, as previously thought, with a progressive deterioration of the immune function, but some important immune parameters are well preserved until the last decades of human life likely contribute to reaching this advanced age.