Among them, lymphopenia and “cytokine storm” are considered to be the main mechanisms resulting in severe COVID-19.1 A number of clinical investigations showed that whether in the peripheral circulation or alveolar lavage fluid, myeloid cells such as monocytes and neutrophils increased, mainly resulting in high levels of inflammatory factors such as interleukin 10 (IL-10) and IL-6. Here, IL10 is linked to lymphopenia.