Biopsies of the inflamed colon of patients suffering from CD and controls were double immunolabelled with anti GFAP (A,D,G,J red) and cCaspase-3 (B,E green) or anti GDNF (H,K green) antibodies and were analyzed by optical sectioning using a confocal microscope. Both antigens, GFAP (A) and c-Caspase-3 (B) can be detected highly in the intestinal wall of the inflamed colon of CD (A,B). The merged images (C) reveal an almost complete overlap of both immunoreactivities (yellow). Only few GFAP-positive cells (D) display no cCaspase-3 immunoreactivity (E) in the control section (F). Although a high immunoreactivity of GDNF (H) in GFAP-positive cells (G,I) and in the epithelial cells of biopsies of patients with CD can be detected, in control biopsies GFAP-positive EGCs (J), which are positioned in the mucosal plexus in close vicinity to the epithelium of the colon, show no GDNF secretion (K,L). Furthermore the subepithelial cells, which express GDNF highly (N, green) showed a colocalization with cCaspase-3 in sections of CD (M-O), whereas in controls no relevant apotosis, proofed by cCaspase-3, or GDNF expression could be detected (P-R). Scale bars, 50 um.