CD4 and COVID-19: In COVID-19 mortality, lymphocyte levels showed a significant negative correlation (OR: 0.41, 95% CI: 0.20-0.85), but it was not significant in the subsets of CD3+ T cells (OR: 0.95, 95% CI: 0.86-1.05), CD4+ T cells (OR: 1.06, 95% CI: 0.86-1.31), CD8+ T cells (OR: 0.38, 95% CI: 0.14-1.01), B cells (OR: 0.98, 95% CI: 0.92-1.04), or NK cells (OR: 0.80, 95% CI: 0.61-1.04).