Bagriacik Umit, Karakus Resul, Yaman Melek, Oruklu Nihan, Araz Milat, Kalayci Zafer, Ozger Hasan Selcuk, Yildiz Yesim, Senol Esin
Department of Immunology, Gazi University, Faculty of Medicine, Ankara, Türkiye.
Department of Infectious Diseases and Clinical Microbiology, Gazi University, Faculty of Medicine, Ankara, Türkiye.
PLoS One. 2025 May 2;20(5):e0321578. doi: 10.1371/journal.pone.0321578. eCollection 2025.
Interleukin 40 (IL-40) is a novel cytokine that has been associated with B lymphocytes, particularly IgA-secreting cells in gut mucosa. Considering mucosal association of IL-40, we aimed to determine serum IL-40 levels in patients with Covid-19. We compared IL-40 concentrations in healthy people to both patients with mild symptoms of SARS-CoV-2 infection and pneumonia. IL-40 was measured by ELISA. Serum IgA levels were tested by nephelometry. For the first time, we demonstrated that SARS-CoV-2 infection increased serum IL-40 levels significantly. The elevation of IL-40 in serum was related to severity of the infection. Therefore, IL-40 concentrations were quite higher in patients with symptoms of pneumonia. Our findings indicated that IgA and NETosis biomarkers were related with IL-40 increase. Based on these findings, we speculated that IL-40 would be associated with immune activities in the mucosa of the lungs of SARS-CoV-2-infected patients. This association may be linked to a mechanism that has a control on IgA and NETosis.
白细胞介素40（IL-40）是一种新型细胞因子，它与B淋巴细胞有关，尤其是肠道黏膜中分泌IgA的细胞。考虑到IL-40与黏膜的关联，我们旨在测定新冠肺炎患者的血清IL-40水平。我们将健康人的IL-40浓度与感染SARS-CoV-2的轻症患者以及肺炎患者进行了比较。通过酶联免疫吸附测定法（ELISA）检测IL-40。通过散射比浊法检测血清IgA水平。我们首次证明，SARS-CoV-2感染显著提高了血清IL-40水平。血清中IL-40的升高与感染的严重程度有关。因此，肺炎患者的IL-40浓度要高得多。我们的研究结果表明，IgA和中性粒细胞胞外诱捕作用（NETosis）生物标志物与IL-40升高有关。基于这些发现，我们推测IL-40可能与SARS-CoV-2感染患者肺部黏膜的免疫活动有关。这种关联可能与一种对IgA和NETosis有调控作用的机制有关。
