The increase in permeability of postcapillary venules in lymph nodes subjected to the regional graft-versus-host reaction.
The changes in permeability of blood vessels in the draining lymph nodes of the footpads undergoing a regional graft-versus-host, host-versus-graft, or antisheep erythrocytes reaction were examined 30 minutes after intravenous injection of Pelikan Ink. Massive leakage of carbon particles was seen only in the postcapillary venules where endothelial cells became flattened. This was observed in lymph nodes 3 to 7 days after induction of the regional graft-versus-host reaction and occurred mainly through intercellular gaps in the endothelium. This transient increase in permeability of postcapillary venules was apparently independent of cellular emigration. No obvious increase in carbon permeability was observed in lymph nodes subjected to the regional host-versus-graft reaction, whereas the uptake of cellular and noncellular elements of the blood by endothelial cells of postcapillary venules was greatly increased. There was no increase in carbon permeability in antisheep erythrocyte-stimulated lymph nodes.
D000818:Animals; D002199:Capillary Permeability; D002244:Carbon / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology; D006087:Graft vs Host Reaction; D006789:Host vs Graft Reaction; D008198:Lymph Nodes / Q000648:ultrastructure; D008208:Lymphatic System / Q000502:physiology*; D008854:Microscopy, Electron; D051381:Rats; D014699:Venules / Q000648:ultrastructure
D002244:Carbon