Neopterin (NPT) is a member of pteridines group, synthesized by macrophages when stimulated by interferon gamma (INF-γ). NPT is regarded as a macrophage stimulation indicator, marker of cellular immune activation and T helper 1 (Th1) type 1 immune response. Here, we aimed to provide a view point on the NPT features and role in Covid-19. Serum NPT level is regarded as an independent prognostic factor for Covid-19 severity, with levels starting to increase from the 3rd day of SARS-CoV-2 infection, being associated with severe dyspnea, longer hospitalization period and complications. Also, early raise of NPT reflects monocytes/macrophages activation before antibody immune response, despite the NPT level may also remain high in Covid-19 patients or at the end of incubation period before the onset of clinical symptoms. On the other hand, NPT attenuates the activity of macrophage foam cells and is linked to endothelial inflammation through inhibition of adhesion molecules and monocytes migration. However, NPT also exerts anti-inflammatory and antioxidant effects by suppressing NF-κB signaling and NLRP3 inflammasomes. NPT can be viewed as a protective compensatory mechanism to counterpoise hyper-inflammation, oxidative stress, and associated organ damage.

Neopterin (NPT) 是蝶啶类的成员，在干扰素γ (INF-γ) 刺激下由巨噬细胞合成。NPT 被视为巨噬细胞刺激指标、细胞免疫激活和 T 辅助细胞 1 (Th1) 1 型免疫反应的标志物。在这里，我们旨在提供一个关于《不扩散核武器条约》的特点和在 Covid-19 中的作用的观点。血清 NPT 水平被认为是 Covid-19 严重程度的独立预后因素，其水平从 SARS-CoV-2 感染的第 3 天开始增加，与严重的呼吸困难、较长的住院时间和并发症有关。此外，尽管 NPT 水平在 Covid-19 患者中或在临床症状出现前的潜伏期结束时也可能保持高水平，但 NPT 的早期升高反映了单核细胞/巨噬细胞在抗体免疫反应之前的激活。另一方面, NPT 减弱巨噬细胞泡沫细胞的活性，并通过抑制粘附分子和单核细胞迁移与内皮炎症有关。然而，NPT 还通过抑制 NF-κB 信号和 NLRP3 炎性体发挥抗炎和抗氧化作用。NPT 可被视为一种保护性补偿机制，可抵消过度炎症、氧化应激和相关器官损伤。