it was seen that ( i ) the duodenum usually had the highest cell counts at all levels of the lamina propria , ( ii ) iga cells in the zone closest to the intestinal lumen became less numerous caudad from the duodenum to the colon , ( iii ) the zone closest to the submucosa ( zone d ) had the fewest iga cells in the small intestines , and ( iv ) the iga cell counts in zone d tended to be lowest in the jejunum and ileum and highest in the duodenum and colon .
C0021852
small intestines
C0022378
jejunum