There was a direct correlation between CD4+ and CD8+ in PCPF patients (p < 0.001; r = 0.90), while in IPF and sarcoidosis patients, CD4+ and CD8+ were inversely correlated (p < 0.001 = −0.87 and p = 0.042; r = −0.6, respectively). This evidence concerns the gene CD4 and idiopathic pulmonary fibrosis.