Figure 2.  Immunohistological characterization of lung tissue. A1–A4, CD26/dipeptidyl peptidase-4 expression in lung tissue. Numerous strongly positive CD26+ cells are seen in the alveolar septa. A3, Intense staining is seen in the type II pneumocytes (arrows). A4, Positive cells are also seen entrapped with fibrin in the vascular lumen. B1–B4, CXCR3/CD183 immunostaining shows intense staining of lymphocytes localized in the inflammatory perivascular aggregates and spread into alveolar septa and alveolar spaces. Scale bars: A1 and B1, 100 µm; A2, A3, and B4, 7 µm; A4, B2, and B3, 14 µm.