CD4 and sarcoidosis: As shown in Fig. 2c, real-time polymerase chain reaction evaluation of TL1A gene expression by highly purified BAL and blood CD4+ T lymphocytes, AMs and monocytes, demonstrated that mRNA expression of TL1A was higher in lung CD4+ T lymphocytes (2.2 ± 1.3) and AMs (3.5 ± 1.6) of active sarcoidosis than in the corresponding cell subsets derived from patients with inactive disease (CD4+ T cells: 0.46 ± 0.16; AMs: 0.64 ± 0.3; p < 0.01 vs active disease), and control subjects (CD4+ T cells: 0.64 ± 0.23; AMs: 0.59 ± 0.3; p < 0.01 vs active disease; ANOVA p < 0.01).