Figure 3
a, IPF/UIP Case 13: a low-magnification view of lung showing normal or minimally involved parenchyma (left) and a large portion of tissue involved by remodeling with large honeycomb cysts reaching the subpleural zone (right) (HE). b, IPF/UIP Case 13: tenascin immunostaining on a serial section to panel a, highlighting ongoing fibrogenesis. Tenascin accumulation is mostly distributed along the boundary zone and around honeycomb cysts. c, IPF/UIP Case 13: the presence of a mural fibroblast focus (arrow) involving an hyperplastic bronchiole, as evidenced by 34βE12 immunostaining. d, IPF/UIP Case 5: a small honeycomb cyst characterized as bronchiolar by 34βE12 cytokeratin expression. e, IPF/UIP Case 5: the bronchiolar nature of the same lesion is confirmed by ΔN-p63 nuclear expression on a serial section. f, IPF/UIP Case 3: a fibroblast focus (FF) formed by spindle-shaped myofibroblasts involving a proliferative epithelial lesion (trichrome stain). g, IPF/UIP Case 3: strong expression of the extracellular matrix protein tenascin in the FF on a serial section to panel f. h, IPF/UIP Case 3: α-smooth muscle actin (α-SMA) expression in spindle-shaped myofibroblasts forming the same FF on a serial section. i, IPF/UIP Case 3: the abnormal cuboidal epithelium lining the same FF is characterized as bronchiolar by the presence of ΔN-p63+ basal cells. j, IPF/UIP Case 3: abnormal accumulation of p53 in scattered epithelial cells of the same lesion (often in basal position). k, IPF/UIP Case 3: nuclear expression of p21waf1 in many epithelial cells of the same lesion. l, IPF/UIP Case 3: decreased expression of the cdk-inhibitor p27kip1 in the epithelial cells lining the FF (compare with the p27kip1 expression of normal bronchiole, as shown in Fig. 2b). m, Acute interstitial pneumonia (AIP): ΔN-p63 is not expressed by hyperplastic alveolar pneumocytes. n, AIP: a large proportion of hyperplastic and/or atypical pneumocytes express transactivating TA-p63 (type II immunoreactivity pattern; see “Materials and Methods”). o, AIP: abnormal p53 nuclear accumulation is evident in hyperplastic pneumocytes.
