Immunology and aging.

Aging is accompanied by numerous functional and phenotypic changes in T cells, B cells and monocytes/macrophages; moreover, increases in autoimmunity, infections and occurrence of cancer have been reported in aged people. Healthy elderly persons, defined according to the criteria of the SENIEUR protocol, show various alterations in immunocompetent cells. Recent data have shown that the distribution of the subsets of peripheral blood, T-cell subtypes, is influenced by age. With increasing age, CD45RA+ naive cells are replaced by CD45RA- memory CD4+ T cells. In the CD8+ T-cell subset, we found an increased proportion of cells co-expressing CD57. In monocytes also, some alterations of the immunophenotype, for example the expression of the adhesion molecule CD54, were observed. A relative deficit of transendothelial migration with aging was found in T cells, whereas this function was not impaired in monocytes. The immunophenotype and the function of dendritic cells do no t appear to be affected by aging. Due ...