CD4 and respiratory failure: ROC analyses for home oxygen therapy prediction of respiratory failure showed a moderate, although significant, prediction (AUC = 0.64, P < 0.01); ROC analyses for CD4+CD8+ T cells% showed similar results (AUC = 0.63, P < 0.02, sensitivity: 47.9%, specificity: 75.0%, Cov ≤ 0.61) (Fig. 3).