Lymphopenia can be caused by direct viral infection since lymphocytes express Angiotensin-converting enzyme 2 (ACE2) (Xu et al., 2020), cytokine storm with a significant increase of IL-6 induce lymphopenia (Tang et al., 2020; Montazersaheb et al., 2022) and lymphocytic infiltration to organs (Proal and VanElzakker, 2021). The gene discussed is ACE2; the disease is viral infectious disease.