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Abstract:

Immunosenescence may be considered as the age-related remodelling of the immune system. The changes occur on different levels of the immune respons. The phenotypic and functional changes in the T-cell component appear to be the most important. The efficacy of the defencemechanisms of the skin, the respiratory and the urinary tract in the innate immune system decreases. There occurs an impaired function of the "natural killer"-cells, which is partially compensated by their increasing number, a diminished activation of the early inflammation and a changing function of the tissue macrophages. In the acquired immunity a shift from naive to memory-T-cells occurs, resulting in a proportional increase of memory cells. Furthermore, there is a shift towards a Th2-anti-inflammatory respons. There is less activation and proliferation of B-cells. As a consequence the incidence of B-cell mediated diseases and the percentage of autoantibodies increase. Some bacterial and viral infections often occur in a geriatric population and involve a high morbidity and mortality. Some infections, for example an infection with the influenzavirus or with Streptococcus pneumoniae, can be prevented by vaccination. In this article we discuss the different aspects of the age-related remodelling of the immune system and their clinical relevance as well as the importance of vaccination in the elderly.