Department of Immunology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan.
AIDS Research Center, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan.
Int Immunol. 2021 Mar 31;33(4):241-247. doi: 10.1093/intimm/dxab005.
An expanded myeloid cell compartment is a hallmark of severe coronavirus disease 2019 (COVID-19). However, data regarding myeloid cell expansion have been collected in Europe, where the mortality rate by COVID-19 is greater than those in other regions including Japan. Thus, characteristics of COVID-19-induced myeloid cell subsets remain largely unknown in the regions with low mortality rates. Here, we analyzed cellular dynamics of myeloid-derived suppressor cell (MDSC) subsets and examined whether any of them correlate with disease severity and prognosis, using blood samples from Japanese COVID-19 patients. We observed that polymorphonuclear (PMN)-MDSCs, but not other MDSC subsets, transiently expanded in severe cases but not in mild or moderate cases. Contrary to previous studies in Europe, this subset selectively expanded in survivors of severe cases and subsided before discharge, but such transient expansion was not observed in non-survivors in Japanese cohort. Analysis of plasma cytokine/chemokine levels revealed positive correlation of PMN-MDSC frequencies with IL-8 levels, indicating the involvement of IL-8 on recruitment of PMN-MDSCs to peripheral blood following the onset of severe COVID-19. Our data indicate that transient expansion of the PMN-MDSC subset results in improved clinical outcome. Thus, this myeloid cell subset may be a predictor of prognosis in cases of severe COVID-19 in Japan.
髓系细胞扩增是严重 2019 冠状病毒病（COVID-19）的标志。然而，关于髓系细胞扩增的数据是在欧洲收集的，那里 COVID-19 的死亡率高于包括日本在内的其他地区。因此，在死亡率较低的地区，COVID-19 诱导的髓系细胞亚群的特征在很大程度上尚不清楚。在这里，我们分析了日本 COVID-19 患者血液样本中髓系来源的抑制细胞（MDSC）亚群的细胞动力学，并研究了它们中的任何一个是否与疾病严重程度和预后相关。我们观察到，多形核（PMN）-MDSC 亚群在严重病例中短暂扩增，但在轻度或中度病例中没有扩增。与欧洲的先前研究相反，该亚群在严重病例的幸存者中选择性扩增，并在出院前消退，但在日本队列中未观察到非幸存者的这种短暂扩增。对血浆细胞因子/趋化因子水平的分析表明，PMN-MDSC 频率与 IL-8 水平呈正相关，表明在严重 COVID-19 发作后，IL-8 参与了 PMN-MDSC 向外周血的募集。我们的数据表明，PMN-MDSC 亚群的短暂扩增导致临床结局改善。因此，该髓系细胞亚群可能是日本严重 COVID-19 病例预后的预测因子。
