CD4 and hypersensitivity pneumonitis: Heron et al. found that combining CD4/CD8 and CD103+CD4+/CD4 ratio can be an specific diagnostic tool (specificity: 92%, positive predictive value: 93%) when considering respective cutoffs of 3 and 0.2, to differentiate patients with sarcoidosis from other interstitial lung diseases, even when CD4 alveolitis is missing [53].