Last update:
08-Apr-2008

During the aging an inflammatory profile is being developed, which is confirmed by the high levels of proinflammatory cytokines and the low level of anti-inflammatory cytokines in the elderly. This change occurs mainly because of the alterations in the immune system. The alterations are summarized as following: in the bone marrow the stromal cells are less efficient to produce the cytokines that are appropriate for the production and maturation of the hematopoietic stem cells, thymus atrophies and in the peripheral lymphoid tissues are observed changes which are possible to influence the maturation of progenital B cells and the capability of immune system for antigenic presentation. As for cells of innate immunity it has been shown that in the monocytes some members of the Toll-like receptors family are underexpressed and are functionally impaired, neutrophils have impaired phagocytosis and chemotaxis and that the number of NK cells is increased and their cytotoxic activities are upregulated. Regarding to the alterations in clonotypic immunity it has been observed that there is a shift in B lymphocytes from B1 to B2, a decrease in the number of antibodies that are specific for an antigen and an increase of the autoantibodies (especially autoantibodies that are not specific for an antigen) and that there is a decrease in the number of naive T-lymphocytes and an accumulation of T memory cells which have low affinity for the antigen. It seems that the enzyme telomerase has a very important role in the changes that are observed in the T cell population (telomerase is a key enzyme for the reproductive ability of the cell). Other factors which are contribute to the changing of the profile into inflammatory are the increased production of free radicals which leads to an augmented function of NFκΒ (basic transcription factor for the expression of proinflammatory cytokines) and other factors, such as zinc decrease that is observed in the elderly.

Key words: Aging, Immune system, Inflammation.