Walker W Allan
Division of Nutrition and Department of Pediatrics, Harvard Medical School, Boston, USA.
Clin Infect Dis. 2008 Feb 1;46 Suppl 2:S87-91; discussion S144-51. doi: 10.1086/523335.
At birth, the newborn leaves the germ-free intrauterine environment and enters a highly contaminated extrauterine world, which requires potent host defenses to prevent disease. Intestinal defenses develop during gestation and have the capacity to respond but first must be exposed to colonizing bacteria. I review the importance of bacterial colonization for the appearance of normal mucosal immune function and the clinical consequences of inadequate colonization with regard to development of disease. For example, we now know that an imbalance in T-helper (Th) cells (e.g., Th2 levels greater than Th1 levels) can predispose to autoimmune disease and gut inflammation or disease, such as necrotizing enterocolitis. As we determine the role of bacterial colonization in the gut (bacterial-epithelial "cross talk"), we should have more-appropriate ways to modulate the gut immune responses-for example, by use of probiotics to prevent the expression of these gastrointestinal diseases.
出生时，新生儿离开无菌的子宫内环境，进入一个高度污染的宫外世界，这需要强大的宿主防御机制来预防疾病。肠道防御在妊娠期发育并具有反应能力，但首先必须接触定植细菌。我将阐述细菌定植对于正常黏膜免疫功能出现的重要性，以及定植不足在疾病发展方面的临床后果。例如，我们现在知道辅助性T细胞（Th）失衡（如Th2水平高于Th1水平）会使人易患自身免疫性疾病和肠道炎症或疾病，如坏死性小肠结肠炎。随着我们确定肠道细菌定植的作用（细菌 - 上皮“相互作用”），我们应该有更合适的方法来调节肠道免疫反应——例如，通过使用益生菌来预防这些胃肠道疾病的发生。
