目的观察过敏性紫癜（ＨＳＰ）患儿急性期的一氧化氮（ＮＯ）及Ⅰ型辅助细胞（ＴＨ１）因子水平，以探讨其在该病全身血管炎发病机制中的作用。方法用镉还原法测定血浆ＮＯ水平，用ＥＬＩＳＡ法检测血浆及外周血单个核细胞（ＰＢＭＣ）培养上清中白细胞介素－２（ＩＬ－２）及干扰素－γ（ＩＦＮ－γ）水平。结果ＨＳＰ急性期血浆ＮＯ水平较对照组明显增高（Ｐ＜００５），血浆ＩＬ－２及ＩＦＮ－γ与正常对照组比较无显著性差异（Ｐ＞００５），但患儿的ＰＢＭＣ培养上清的ＩＬ－２及ＩＦＮ－γ明显低于正常对照组（Ｐ＜００５）。结论ＮＯ及ＴＨ１细胞因子在ＨＳＰ全身血管炎的发生、发展中起作用 Objective To investigate the levels of nitric oxide (NO) and type Ⅰ helper cell (TH1) in children with Henoch-Schonlein Purpura (HSP) during acute phase to investigate the role of nitric oxide (NO) and type I helper cells (TH1) in pathogenesis of systemic vasculitis. Methods Plasma NO level was measured by cadmium reduction method. The levels of interleukin-2 (IL-2) and interferon-γ (IFN-γ) in the culture supernatant of plasma and peripheral blood mononuclear cells (PBMC) were detected by ELISA. Results The level of plasma NO in acute phase of HSP was significantly higher than that of the control group (P <005), but there was no significant difference between the plasma levels of IL-2 and IFN-γ and the normal control group (P> 005) The levels of IL-2 and IFN-γ in the culture supernatant were significantly lower than those in the normal control group (P <005). Conclusion NO and TH1 cytokines play a role in the occurrence and development of HSP vasculitis