CD4 and COVID-19: While the mechanism that might explain the association between lymphocytopenia and poor patients’ outcome in COVID-19 patients is not fully understood, previous reports in other similar beta-CoV infections including (SARS)-CoV and (MERS)- CoV highlighted the possible role of lymphocyte sequestration in specific target organs which might lead to rapid reduction in both CD4+ and CD8+ T lymphocytes [53].