Datasheet1_Gut microbiota alterations in children and their relationship with primary immune thrombocytopenia.docx

IntroductionGut microbiota reportedly play a critical role in some autoimmune diseases by maintaining immune homeostasis. Only a few studies have examined the correlation between gut microbiota and the onset of primary immune thrombocytopenia (ITP), especially in children. The purpose of this study was to investigate changes in the composition and diversity of the fecal microbiota of children with ITP, as well as the correlation between such microbiota and the onset of ITP.
MethodsTwenty-five children newly diagnosed with ITP and 16 healthy volunteers (controls) were selected for the study. Fresh stool samples were collected to identify changes in the composition and diversity of gut microbiota as well as for potential correlation analysis.
ResultsIn ITP patients, the phyla that were most frequently encountered were Firmicutes (54.3%), followed by Actinobacteria (19.79%), Bacteriodetes (16.06%), and Proteobacteria (8.75%). The phyla that were predominantly found in the controls were, Firmicutes (45.84%), Actinobacteria (40.15%), Bacteriodetes (3.42%), and Proteobacteria (10.23%). Compared with those of the controls, the proportions of Firmicutes and Bacteriodetes in the gut microbiota of ITP patients were increased while the proportions of Actinobacteria and Proteobacteria were decreased. Furthermore, gut microbiota in ITP patients varied by age group, showed specific changes in diversity, and were correlated with antiplatelet antibodies. IgG levels were significantly positively correlated with Bacteroides (P<0.01).
ConclusionsThe gut microbiota of children with ITP are imbalanced, as shown by the increase in Bacteroidetes, which was positively correlated with IgG. Thus gut microbiota may contribute to ITP pathogenesis via IgG.
Clinical Trial RegistrationThe clinical trial were registered and approved by the Institutional Review Committee of The Affiliated Huaian No.1 People’s Hospital of Nanjing Medical University. Ethics number KY-2023-106-01.

引言 据报道，肠道菌群（gut microbiota）通过维持免疫稳态，在部分自身免疫性疾病中发挥关键作用。目前仅有少数研究探讨了肠道菌群与原发性免疫性血小板减少症（primary immune thrombocytopenia, ITP）发病的相关性，针对儿童群体的相关研究尤为匮乏。本研究旨在探究ITP患儿粪便菌群（fecal microbiota）的组成与多样性变化，以及此类菌群与ITP发病的相关性。
方法 本研究纳入25例初诊ITP患儿及16名健康志愿者（对照组），采集新鲜粪便样本以分析肠道菌群组成与多样性变化，并开展潜在相关性分析。
结果 ITP患者粪便菌群中丰度最高的菌门依次为厚壁菌门（Firmicutes，54.3%）、放线菌门（Actinobacteria，19.79%）、拟杆菌门（Bacteroidetes，16.06%）及变形菌门（Proteobacteria，8.75%）；对照组粪便菌群的优势菌门则为厚壁菌门（45.84%）、放线菌门（40.15%）、拟杆菌门（3.42%）及变形菌门（10.23%）。与对照组相比，ITP患者肠道菌群中厚壁菌门与拟杆菌门占比升高，而放线菌门与变形菌门占比降低。此外，ITP患儿的肠道菌群存在年龄组间差异，多样性呈现特异性变化，且与抗血小板抗体（antiplatelet antibodies）相关。其中免疫球蛋白G（Immunoglobulin G, IgG）水平与拟杆菌属（Bacteroides）呈显著正相关（P<0.01）。
结论 ITP患儿肠道菌群存在失衡，表现为拟杆菌门丰度升高，且该菌门与IgG水平呈正相关。提示肠道菌群可能通过IgG参与ITP的发病机制。
临床试验注册 本临床试验已获得南京医科大学附属淮安第一医院伦理委员会注册批准，伦理编号为KY-2023-106-01。