Forsberg A, West C E, Prescott S L, Jenmalm M C
Division of Neuro and Inflammation Sciences, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
International Inflammation (in-FLAME) network of the World Universities Network, Umeå, Sweden.
Clin Exp Allergy. 2016 Dec;46(12):1506-1521. doi: 10.1111/cea.12838.
Reduced intensity and diversity of microbial exposure is considered a major factor driving abnormal postnatal immune maturation and increasing allergy prevalence, particularly in more affluent regions. Quantitatively, the largest important source of early immune-microbial interaction, the gut microbiota, is of particular interest in this context, with variations in composition and diversity in the first months of life associated with subsequent allergy development. Attempting to restore the health consequences of the 'dysbiotic drift' in modern society, interventions modulating gut microbiota for allergy prevention have been evaluated in several randomized placebo-controlled trials. In this review, we provide an overview of these trials and discuss recommendations from international expert bodies regarding prebiotic, probiotic and synbiotic interventions. Recent guidelines from the World Allergy Organization recommend the use of probiotics for the primary prevention of eczema in pregnant and breastfeeding mothers of infants at high risk for developing allergy and in high-risk infants. It is however stressed that these recommendations are conditional, based on very low-quality evidence and great heterogeneity between studies, which also impedes specific and practical advice to consumers on the most effective regimens. We discuss how the choice of probiotic strains, timing and duration of administration can critically influence the outcome due to different effects on immune modulation and gut microbiota composition. Furthermore, we propose strategies to potentially improve allergy-preventive effects and enable future evidence-based implementation.
微生物暴露强度和多样性的降低被认为是导致出生后免疫成熟异常和过敏患病率上升的主要因素，在较富裕地区尤其如此。从数量上看，早期免疫与微生物相互作用的最重要来源——肠道微生物群，在这方面尤其受到关注，生命最初几个月其组成和多样性的变化与随后的过敏发展有关。为了恢复现代社会中“生态失调漂移”对健康造成的影响，已经在多项随机安慰剂对照试验中评估了调节肠道微生物群以预防过敏的干预措施。在本综述中，我们概述了这些试验，并讨论了国际专家机构关于益生元、益生菌和合生元干预措施的建议。世界过敏组织最近的指南建议，对于有过敏高风险的婴儿的孕妇和哺乳期母亲以及高风险婴儿，使用益生菌进行湿疹的一级预防。然而，需要强调的是，这些建议是有条件的，基于非常低质量的证据以及研究之间的巨大异质性，这也阻碍了向消费者提供关于最有效方案的具体实用建议。我们讨论了益生菌菌株的选择、给药时间和持续时间如何由于对免疫调节和肠道微生物群组成的不同影响而对结果产生关键影响。此外，我们提出了一些策略，以潜在地提高预防过敏的效果，并实现未来基于证据的实施。
