Observations on aggregated lymphoid nodules in the cardiac glandular areas of the Bactrian camel (Camelus bactrianus).

Aggregated lymphoid nodules are an important part of the gut-associated lymphoid tissue (GALT). They are mainly distributed in the ileum and appendix of animals and humans but their distribution in the cardiac glandular area has not been reported. A study of stomach histology in the Bactrian camel has revealed that the nodules are distributed as a band-like region along the ventral wall of the stomach neck, at the beginning of the cranial enlargement and on the lesser curvature. The mucous folds are thicker in these regions than where there are no aggregated lymphoid nodules. The nodules appeared similar to ileal aggregated lymphoid nodules found in other animals and consisted of typical polymorphological lymphatic nodules arranged in a single continuous row occupying the submucosa and forming mucosal folds together with the mucous membrane. The whole mucous membrane with cardiac glands, diffuse lymphatic tissue and solitary lymphoid nodules in the lamina propria were found to cover the aggregated lymphoid nodule regions, but some nodules with a typical corona extended into the lamina propria and were covered with follicle-associated epithelium devoid of cardiac glands. These findings indicate that the stomach of the Bactrian camel possesses not only a special structure of digestion but also has characteristic immunological morphology.