Finally, examination of PD-1 expression in matching sarcoidosis BAL and PBMC demonstrated significantly more PD-1+CD4+ cells in BAL than in PBMC, in which on average 25.1% versus 8.4% PD-1+CD4+ cells are present, respectively (Figure 6(f); p < 0.05). This evidence concerns the gene CD4 and sarcoidosis.