In our study, well-documented hallmarks of severe COVID-19, such as lymphopenia, a higher neutrophil-to-lymphocyte ratio (NEU/LYM), and the proinflammatory cytokine storm including IL-6, IL-1β, IL-8, and TNF-α were observed in adult COVID-19 patients rather than pediatric patients. The gene discussed is CXCL8; the disease is lymphopenia.