Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA.
J Allergy Clin Immunol. 2010 Feb;125(2 Suppl 2):S262-71. doi: 10.1016/j.jaci.2009.10.063.
The term complement was introduced more than 100 years ago to refer to a group of plasma factors important in host defense and in the destruction of microorganisms. We now know that there are 3 separate activation pathways that appeared at different times in evolution: the classical, alternative, and lectin pathways. Two of these appear before the evolution of the adaptive immune system and do not require antibody for initiation. All pathways come together to activate C3, the principle opsonic protein of the complement cascade, and all continue together to the generation of biologically active factors, such as C5a, and to lysis of cells and microbes. In general, complete deficiencies of complement proteins are rare, although partial or complete deficiencies of one of the proteins that initiates the lectin pathway, mannose-binding lectin, are far more common. Although genetically controlled complement defects are rare, defects in the proteins in the circulation and on cell membranes that downregulate complement so as to limit uncontrolled inflammation are more common. A number of these are discussed, and because new methods of treatment are currently being introduced, one of these defects, CI inhibitor deficiency associated with hereditary angioedema, is discussed in some detail.
补体一词在 100 多年前被引入，是指一组在宿主防御和微生物破坏中起重要作用的血浆因子。我们现在知道，有 3 种独立的激活途径，它们在进化的不同时期出现：经典途径、替代途径和凝集素途径。其中两种途径出现在适应性免疫系统进化之前，不需要抗体即可启动。所有途径都汇聚到一起激活 C3，即补体级联反应的主要调理蛋白，然后一起继续生成生物活性因子，如 C5a，并导致细胞和微生物的裂解。一般来说，补体蛋白的完全缺乏是罕见的，尽管凝集素途径起始蛋白之一甘露聚糖结合凝集素的部分或完全缺乏要常见得多。虽然遗传控制的补体缺陷很少见，但在循环中和细胞膜上调节补体以限制失控性炎症的蛋白质缺陷更为常见。本文讨论了其中的一些缺陷，并由于目前正在引入新的治疗方法，因此详细讨论了其中一种缺陷，即与遗传性血管性水肿相关的 C1 抑制剂缺乏。
