Eosinophils are circulating and tissue-resident leukocytes that have potent proinflammatory effects in a number of diseases. Recently, eosinophils have been shown to have various other functions, including immunoregulation and antiviral activity. Eosinophil levels vary dramatically in a number of clinical settings, especially following eosinophil-targeted therapy, which is now available to selectively deplete these cells. There are key coronavirus disease 2019 (COVID-19)-related questions concerning eosinophils whose answers affect recommended prevention and care. First, do patients with eosinophilia-associated diseases have an altered course of COVID-19? Second, do patients with eosinopenia (now intentionally induced by biological drugs) have unique COVID-19 susceptibility and/or disease course? This is a particularly relevant question because eosinopenia is associated with acute respiratory deterioration during infection with the severe acute respiratory syndrome coronavirus 2, the causative agent of COVID-19. Third, do eosinophils contribute to the lung pathology induced during COVID-19 and will they contribute to immunopotentiation potentially associated with emerging COVID-19 vaccines? Herein, we address these timely questions and project considerations during the emerging COVID-19 pandemic.

嗜酸性粒细胞是循环的和组织驻留的白细胞，在许多疾病中均具有有效的促炎作用。近来，嗜酸性粒细胞已显示具有多种其他功能，包括免疫调节和抗病毒活性。嗜酸性粒细胞水平在许多临床环境中变化很大，尤其是在针对嗜酸性粒细胞的治疗后，现在可用于选择性消耗这些细胞。关于嗜酸性粒细胞，存在与冠状病毒疾病2019（COVID-19）相关的关键问题，其答案影响建议的预防和护理。首先，嗜酸性粒细胞相关疾病患者的COVID-19病程是否改变？第二，嗜曙红细胞减少症（现已由生物药物有意诱导）的患者是否具有独特的COVID-19易感性和/或疾病进程？这是一个特别相关的问题，因为在感染严重急性呼吸综合征冠状病毒2（COVID-19的致病因子）期间，嗜曙红细胞减少症与急性呼吸恶化有关。第三，嗜酸性粒细胞是否有助于在COVID-19期间诱导的肺部疾病，并且它们是否会有助于与新兴COVID-19疫苗相关的免疫增强作用？在此，我们在新兴的COVID-19大流行期间解决这些及时的问题和项目考虑因素。嗜酸性粒细胞是否有助于在COVID-19期间诱导的肺部病理，是否会促进与新兴COVID-19疫苗潜在相关的免疫增强作用？在此，我们在新兴的COVID-19大流行期间解决这些及时的问题和项目考虑因素。嗜酸性粒细胞是否有助于在COVID-19期间诱导的肺部病理，是否会促进与新兴COVID-19疫苗潜在相关的免疫增强作用？在此，我们在新兴的COVID-19大流行期间解决这些及时的问题和项目考虑因素。