Ongrádi J, Stercz B, Kövesdi Valéria, Vértes L
Institute of Public Health, Semmelweis University, Budapest Hungary.
Acta Microbiol Immunol Hung. 2009 Sep;56(3):199-210. doi: 10.1556/AMicr.56.2009.3.1.
The sharp increase of life expectancy and the increasing ratio of ageing population pose new challenges for the public health system. The elderly suffer from more frequent and severe infections than young people. Theoretically, vaccination could protect the elderly against several infectious diseases, but due to their age-related immune impairment, vaccination might fail in many cases. Instead of ineffective vaccination campaigns, exploration and restoration of age-dependent dysregulation of their immune functions have to be placed into the focus of recent research. Frequent comorbidities in these people augment immune defects. Immunosenescence affects both the innate and adaptive immunity. Disturbances in macrophage-derived cytokine release and reduction of the natural killer cell mediated cytotoxicity lead to increased frequency of respiratory, gastrointestinal and skin infections. Although the humoral immunity retains most of its original activity through life span, ageing dampens the ability of B cells to produce antibodies against novel antigens. Age-related declination of the cellular immunity is the consequence of thymic atrophy, reduced output of new T lymphocytes, accumulation of anergic memory cells, deficiencies in the cytokine production and uncertain antigen presentation. Persistent infection by different herpesviruses and other parasites contribute to the loss of immunosurveillance and premature exhaustion of T cells.
预期寿命的急剧增加和老龄化人口比例的上升给公共卫生系统带来了新的挑战。老年人比年轻人更容易遭受频繁且严重的感染。理论上，接种疫苗可以保护老年人免受多种传染病的侵害，但由于与年龄相关的免疫功能受损，疫苗接种在很多情况下可能会失败。与其开展无效的疫苗接种活动，探索并恢复其免疫功能的年龄依赖性失调必须成为近期研究的重点。这些人群中常见的合并症会加剧免疫缺陷。免疫衰老会影响固有免疫和适应性免疫。巨噬细胞衍生的细胞因子释放紊乱以及自然杀伤细胞介导的细胞毒性降低，导致呼吸道、胃肠道和皮肤感染的频率增加。尽管体液免疫在整个生命周期中大部分保留了其原始活性，但衰老会削弱B细胞产生针对新抗原的抗体的能力。与年龄相关的细胞免疫衰退是胸腺萎缩、新T淋巴细胞输出减少、无反应性记忆细胞积累、细胞因子产生缺陷以及抗原呈递不确定的结果。不同疱疹病毒和其他寄生虫的持续感染导致免疫监视功能丧失和T细胞过早耗竭。
