Peyer's patches export lymphocytes throughout the lymphoid system in XXXX .

@entity2822 @entity1600 @entity742
The lymphocyte output from small intestine containing either the long continuous ileal Peyer's patch (PP) or several smaller jejunal PP was examined in young @entity742 . Most studies were done in 2-mo-old @entity742 , 1 mo after removal of @entity1600 ( @entity1600 ). Extracorporeal perfusion of part of the intestine and addition of @entity2822 to the perfusate led to the labeling, in their normal microenvironment, of a regionally defined population of cells. One day later considerable numbers of emigrant lymphocytes were identified by fluorescence microscopy in the spleen, @entity1600 and peripheral lymph nodes, jejunal PP, and bone marrow. In nonperfused ileal PP and thymus the labeling indexes were low. The highest labeling index was in the blood where 3.7% of the lymphocytes were labeled. A similar organ distribution of emigrant cells was found on day 3. When @entity1600 were included in the perfused region more emigrants were identified. In some animals the intestinal lymphatic draining the perfused ileum was cannulated. Continual lymph drainage caused a dramatic decrease in the labeling indexes in other lymphoid organs. A substantial number of lymphocytes leave both ileal PP and jejunal PP via lymphatics and travel to all other lymphoid organs. However, the number of emigrant lymphocytes compared with the total number of labeled lymphocytes in the perfused tissue was about 10 times greater after perfusing gut with the jejunal PP than after ileal PP perfusion. We conclude that relatively more lymphocytes emigrate from the jejunal PP than from the ileal PP.
