ICAM1 and idiopathic pulmonary fibrosis: The number of ICAM–1 positive type 2 pneumocytes per mm2 in alveolar area is significantly higher in IPF (median 668,143 cells per mm2, range 168,350–2,253,902 cells per mm2) compared to NC (median 169,437 cells per mm2, range 28,250–611,925 cells per mm2, p = 0.0010) (Figure 4C), and in contrast, the number of ICAM–1 negative type 2 pneumocytes is significantly higher in NC (median 307,286 cells per mm2, range 82,058–713,380 cells per mm2) compared to IPF (median 69,772 cells per mm2, range 8858–210,993 cells per mm2, p = 0.0010) (Figure 4D).