Platelet P-selectin expression was significantly greater in IPF patients than controls following stimulation with 0.1 μM ADP (1.9% positive ±0.5 (mean ± SEM) versus 0.7%±0.1; p = 0.03), 1 μM ADP (9.8%±1.3 versus 3.3%±0.8; p<0.01) and 10 μM ADP (41.3%±4.2 versus 22.5%±2.6; p<0.01). This evidence concerns the gene SELP and idiopathic pulmonary fibrosis.