CD4 and COVID-19: The meta-analysis of Feng and colleagues [29] confirmed previously mentioned findings about the levels of PCT, CRP, erythrocyte sedimentation rate (ESR) and IL-6, as well as the fact that increased WBC, decreased numbers of total lymphocytes and subtypes, such as CD4+T and CD8+T, and increased NLR are considered as risk factors for disease progression in patients with COVID-19.