Elevated local production of neopterin from alveolar macrophages in patients with internal lung diseases

1. We measured the neopterin level in the supernatant of cultured alveolar macrophages from patients with interstitial lung diseases (ILD patients) as a marker for the activation of alveolar macrophage. 2. In ILD patients, the supernatant neopterin level (40.1 +/- 7.8 pmol/ml) was significantly higher (P < 0.01) than that in control subjects (10.0 +/- 1.6 pmol/ml). 3. We also found that macrophage-colony stimulating factor (M-CSF) and interleukin-2 (IL-2) augmented neopterin production from alveolar macrophage in both ILD patients (51.6 +/- 10.4 and 60.1 +/- 10.8 pmol/ml, respectively, P < 0.01) and control subjects (28.1 +/- 6.0 and 25.7 +/- 4.9 pmol/ml, respectively). 4. These findings suggest that alveolar macrophages produce neopterin by M-CSF or IL-2.