【摘要】 目的 探讨0～2岁过敏性疾病（特应性皮炎、哮喘）患儿与健康婴幼儿肠道s IgA包被菌的丰度及组成差异，并初步探讨其与部分免疫指标的相关性。方法 选取2023年1月至2023年10月在大连市妇女儿童医疗中心就诊的0～2岁过敏性疾病患儿作为过敏组（n=29），并招募同期年龄匹配的健康婴幼儿作为对照组（n=30）。收集两组对象血清检测免疫指标（包括C3、C4、IgE等）及淋巴细胞亚群（CD3+、CD19+）。采用磁激活细胞分选技术（MACS）分选粪便sIgA包被菌，进行16S rRNA基因测序分析菌群组成。对关键菌属与免疫指标进行相关性分析。结果 过敏组婴幼儿肠道sIgA包被菌的alpha多样性与对照组无显著差异（均P>0.05）。在菌群组成上，过敏组sIgA包被菌中厚壁菌门丰度升高（59.65%vs. 48.95%），放线菌门丰度降低（22.78%vs. 35.84%）；属水平上链球菌属（8.42%vs. 4.02%）和科林斯菌属（1.73%vs. 0.59%）丰度升高，双歧杆菌属（20.29%vs. 34.61%）和肠球菌属（3.22%vs. 7.65%）丰度降低；种水平上齿双歧杆菌（0.07%vs.3.56%）和短双歧杆菌（3.40%vs. 6.15%）丰度显著下降（均P<0.05）。免疫指标方面，过敏组血清总IgE(t=5.272,P<0.001)和CD19+B细胞比例（t=3.278,P=0.002）均显著高于对照组；补体C3水平虽有升高趋势，但差异无统计学意义（t=1.634,P=0.108）;CD3+T细胞比例虽有降低趋势，但差异亦无统计学意义（t=1.271,P=0.209）。相关性分析显示，链球菌属丰度与CD19+B细胞比例（r=0.673, P<0.001）及补体C3水平（r=0.787,P<0.001）呈正相关，而与CD3+T(r=-0.571,P<0.001)细胞比例呈负相关。结论 过敏性疾病婴幼儿肠道sIgA包被菌群呈现特征性改变，主要表现为链球菌富集与双歧杆菌减少，且该菌群特征与系统性B细胞、补体激活及T细胞比例存在显著相关性，提示肠道菌群sIgA包被状态可能与系统性免疫细胞平衡存在关联，为从黏膜免疫角度探索过敏性疾病的早期发生提供了新的微生物与免疫线索。更多还原

【Abstract】 Objective To observe the differences in the abundance and composition of intestinal sIgA-coated bacteria between infants and young children(aged 0 to 2 years) with allergic diseases(atopic dermatitis, asthma) vs. healthy controls, and preliminarily explore their correlation with certain immune indicators. Methods Children aged 0 to 2 years with allergic diseases who visited the hospital from January 2023 to October 2023 were enrolled as the allergy group(n=29). Age-matched healthy infants and toddlers were recruited during the same period as the control group(n=30).Serum samples were collected to detect immune indicators(including C3, C4, IgE, etc.) and lymphocyte subsets(CD3+,CD19+). Fecal sIgA-coated bacteria were sorted using magnetic-activated cell sorting(MACS), and their composition was analyzed using 16S rRNA sequencing. Correlation analysis was conducted between key genera and immune indicators.Results There was no significant difference in the alpha diversity of intestinal sIgA-coated bacteria between the allergy group and healthy control group. Regarding bacterial composition, the abundance of Firmicutes increased, while Actinobacteria decreased in the sIgA-coated bacteria in the allergy group. At the genus level, the abundances of Streptococcus and Collinsella increased, whereas Bifidobacterium and Enterococcus decreased(all P<0.05). At the species level, the abundances of Bifidobacterium dentium and Bifidobacterium breve significantly reduced. Regarding immune parameters, the allergy group exhibited significantly higher serum total IgE(t=5.272, P<0.001) and percentage of CD19+B cells(t=3.278, P=0.002) than the control group. Complement C3 levels tended to increasewithout statistical significance(t=1.634, P=0.108), while the percentage of CD3+T cells tended to decrease, also with no statistical significance(t=1.271, P=0.209). Correlation analysis showed that the abundance of Streptococcus was positively correlated with the proportion of CD19+B cells(r=0.673, P<0.001) and complement C3 levels(r=0.787, P<0.001), and negatively correlated with the proportion of CD3+T cells(r=-0.571, P<0.001). Conclusion This study identified characteristic alterations in the intestinal sIgA-coated microbiota in infants and toddlers with allergic diseases, primarily characterized by an enrichment of Streptococcus and a reduction in Bifidobacterium. These microbial features were significantly correlated with systemic B cell and complement activation, as well as T cell proportions. This suggests that the sIgA-coating status of gut microbiota may be linked to the balance of systemic immune cells, providing new microbial and immune clues for exploring early development of allergic diseases from the perspective of mucosal immunity.更多还原