T-cell activation is modulated by dipeptidyl peptidase-4 (DPP4) [16] and thus the expression of CD26/DPP4 and CXCR3/CD183 was analyzed on lung tissues from group 2 patients (Figure 2). Numerous CD26+ cells were found in the alveolar septa (Figure 2A1–2A3) with intense staining seen in the type II pneumocytes (Figure 2A3). Positive cells entrapped with fibrin clots in the vascular lumen were also observed (Figure 2A4). CXCR3 immunostaining showed lymphocytes localized in inflammatory perivascular aggregates (Figure 2B1, 2B2, and 2B4) which spread into alveolar septa and alveolar spaces (Figure 2B2 and 2B3).