MCS Hospital and MMC Clinic Muvattupuzha, Ernakulam dist. Pin:686661, Kerala, India.
Indian J Tuberc. 2022;69 Suppl 2:S241-S245. doi: 10.1016/j.ijtb.2022.10.012. Epub 2022 Oct 26.
The article reviews the immune changes in the elderly with particular reference to susceptibility of elderly to Tubercular infection whether new or LTBI and in the light of recent advances in the field of immune mechanisms of tubercular infection. An primary understanding of the host response to infections and M. tuberculosis (M.tb) infection in particular helps to better understand the various issues of immune response to tubercular infection in the elderly. Immune mechanisms of ageing in particular deal with the twin unique mechanisms and terms particular to aging- Immunosenescence and Inflammaging. In the elderly patient both the Innate and the Adaptive immune responses are affected at various levels. The M.tb bacteria encounters the innate immune system initially and thereafter the response is from the cells of the adaptive immune system. The M.tb bacillus which enters through the respiratory system to the bronchioles and alveolus encounters the immune system at three levels which are the Resident structural i.e. alveolar epithelium, Resident innate i.e. the alveolar and pulmonary macrophages and the Infiltrating innate i.e. the neutrophils and monocytes. Increased inflammatory changes present in the lung mucosa has been associated with changes in multiple innate molecular defence mechanisms that could influence the ability of M.tb to establish an infection, the various cellular mechanisms involved and the evasive strategies evolved by the M.tb to survive and disseminate are briefly described. The susceptibility of the elderly to develop and succumb to TB may be a direct impact of increased inflammation at every stage of infection. M.tb is a potent stimulator of multiple inflammatory responses and added to a basal inflammatory state with evasiveness of M.tb bacilli, enable it to overcome and disseminate, increasing the morbidity and mortality in the infected elderly. Hopefully a better understanding of the immune mechanisms involved will enable better preventive, diagnostic and treatment modalities.
这篇文章回顾了老年人的免疫变化，特别是老年人对新的或 LTBI 结核感染的易感性，并结合了近年来在结核感染免疫机制领域的进展。对宿主对感染和结核分枝杆菌（M.tb）感染的反应的初步了解有助于更好地理解老年人对结核感染免疫反应的各种问题。特别是，免疫衰老和炎症衰老这两个独特的机制和术语与衰老的免疫机制有关。在老年人中，固有免疫和适应性免疫反应都在不同层面受到影响。M.tb 细菌最初遇到固有免疫系统，然后是适应性免疫系统的细胞做出反应。进入细支气管和肺泡的 M.tb 杆菌在三个层面遇到免疫系统，即驻留结构（即肺泡上皮）、驻留固有（即肺泡和肺巨噬细胞）和浸润固有（即中性粒细胞和单核细胞）。肺黏膜中增加的炎症变化与多种固有分子防御机制的变化有关，这些变化可能影响 M.tb 建立感染的能力、涉及的各种细胞机制以及 M.tb 为生存和传播而产生的逃避策略。老年人易患和死于结核病可能是感染各个阶段炎症增加的直接影响。M.tb 是多种炎症反应的有效刺激物，加上 M.tb 杆菌的基本炎症状态和逃避能力，使它能够克服和传播，增加感染老年人的发病率和死亡率。希望对涉及的免疫机制有更好的理解将能够实现更好的预防、诊断和治疗方式。
