Henoch–Schönlein purpura (HSP) is the most common immunoglobulin A-mediated systemic vasculitis in childhood. We studied immune dysregulation in HSP by analyzing regulatory T (Treg), T helper 3 (Th3), and regulatory B cell (Breg) subpopulations that might intervene in immune activation, IgA production, and HSP clinical manifestations. This prospective study included 3 groups of children: 30 HSP on acute phase, 30 HSP on remission, and 40 healthy controls (HCs) matched on age. Treg, Breg, and Th3 were analyzed by flow cytometry. Serum immunoglobulin and cytokine levels were quantified by ELISA and Luminex. Treg frequencies were higher in acute HSP than in remitting HSP and HCs (6.53% [4.24; 9.21] vs. 4.33% [3.6; 5.66], p = 0.002, and vs. 4.45% [3.01; 6.6], p = 0.003, respectively). Activated Th3 cells (FoxP3 + Th3 cells) tend to be more abundant in HSP than in HCs (78.43% [50.62; 80.84] vs. 43.30% [40.20; 49.32], p = 0.135). Serum IgA, IL-17, and latency-associated peptide (a marker of the anti-inflammatory cytokine TGF-beta production) were significantly and inflammatory cytokines TNF-alpha, IL-1-beta, and IL-6 were non-significantly higher in HSP than HCs. Bregs were identical between the groups, but, in patients with renal impairment, Breg percentage was lower compared to those without. Treg removal in PBMC culture resulted in an increase in IgA production in HSP proving a negative regulatory role of Tregs on IgA production. In pediatric HSP, immune activation persists in spite of an increase in Th3 and Tregs. Th3 could be involved in IgA hyperproduction, inefficiently downregulated by Tregs. Lack of Bregs appears linked to renal impairment.

中文翻译：

---

小儿过敏性紫癜中的调​​节性 T 细胞和 B 细胞：朋友还是敌人？

过敏性紫癜 (HSP) 是儿童时期最常见的免疫球蛋白 A 介导的系统性血管炎。我们通过分析可能干预免疫激活、IgA 产生和 HSP 临床表现的调节性 T (Treg)、T 辅助细胞 3 (Th3) 和调节性 B 细胞 (Breg) 亚群来研究 HSP 中的免疫失调。这项前瞻性研究包括 3 组儿童：30 名急性期 HSP，30 名缓解期 HSP，以及 40 名年龄匹配的健康对照 (HC)。通过流式细胞术分析 Treg、Breg 和 Th3。通过 ELISA 和 Luminex 定量血清免疫球蛋白和细胞因子水平。急性 HSP 中的 Treg 频率高于缓解期 HSP 和 HC（6.53% [4.24; 9.21] 与 4.33% [3.6; 5.66]，p = 0.002，以及 4.45% [3.01; 6.6]，p = 0.003，分别）。活化的 Th3 细胞（FoxP3 + Th3 细胞）在 HSP 中比在 HC 中更丰富（78.43% [50.62; 80.84] vs. 43.30% [40.20; 49.32]，p = 0.135）。血清 IgA、IL-17 和潜伏相关肽（抗炎细胞因子 TGF-β 产生的标志物）显着升高，而炎症细胞因子 TNF-α、IL-1-β 和 IL-6 则非显着升高HSP 中的值高于 HC。各组之间的 Breg 是相同的，但在肾功能不全的患者中，Breg 百分比低于那些没有肾功能不全的患者。 PBMC 培养物中 Treg 的去除导致 HSP 中 IgA 产量的增加，证明 Tregs 对 IgA 产量具有负调节作用。在儿童 HSP 中，尽管 Th3 和 Tregs 有所增加，但免疫激活仍然存在。 Th3 可能参与 IgA 过度生成，但被 Tregs 低效下调。 Bregs 缺乏似乎与肾功能损害有关。