Chronic intestinal ulceration in Crohn's disease is associated with the development of an epidermal growth factor-secreting cell lineage, or 'ulcer-associated cell lineage' (UACL). Expression of oligosaccharides by UACL was studied using a panel of 25 biotinylated lectins with an avidin peroxidase revealing system and compared with that of adult and fetal Brunner's glands, gastric antral mucosa, and 'gastric metaplasia' within the duodenum, in order to clarify further the interrelationships of these lineages. UACL was obtained from ileal resections performed for Crohn's disease. Lectin binding of the glandular component of UACL closely resembled that of antral mucosal glands and also that of fetal and adult Brunner's glands. Lectin binding of the ductal component of immature UACL, in which a surface component had not developed, resembled that of the gland. The surface and ductal components of mature UACL showed a distinct lectin-binding profile, which was very different from that of the gland, but closely resembled that of antral foveolar epithelium and 'gastric metaplasia' within the duodenum. It is concluded that there is differentiation of UACL from the glandular to surface components and that oligosaccharide expression of the lineage reflects that of normal Brunner's gland and gastric antral mucosa.