Figure 2. Immunohistochemical staining with PAI-1, α-SMA and IL-4. Cell expressions of PAI-1, α-SMA and IL-4 in septal interstitium and intrapulmonary vessels from normal and systemic sclerosis (SSc) lung tissue are shown. There is a diffuse and increased expression of PAI-1 (arrows) (D), α-SMA (arrows) (E) and IL-4 (arrows) (F) in the septal interstitium of cellular nonspecific interstitial pneumonia (NSIP) contrasting with a minimal or without expression of PAI-1 (arrows) (A), α-SMA (B) and IL-4 (arrows) (C) of the control group. Comparing the expression of PAI-1, α-SMA, and IL-4 between the cellular (D,E,F) and fibrotic (G,H,I) NSIP pattern, a higher expression of α-SMA in fibrotic than in cellular NSIP was observed. Increased expression of PAI-1, α-SMA and IL-4 is observed in cellular (arrows) (M,N,O) and fibrotic (arrows) (P,Q,R) NSIP groups when compared with the control (arrows) (J,K,L) group.