In CF patients, the total mast cell (MCtot) expression of IL-6 was increased in small airways (40 [25-75]%), pulmonary vessels (73 [48-83]%) and alveolar parenchyma (30 [20-39]%) compared to controls (small airways: 11 [0-22]%, p = 0.006; pulmonary vessels: 22 [0-73]%, p = 0.01; and alveolar parenchyma: 8 [0-56]%, p = 0.05). The gene discussed is IL6; the disease is cystic fibrosis.