Characteristic changes are produced in the lymph nodes of rabbits following the intravenous injection of certain bacterial filtrates administered 24 hours after either an intralymphatic or an intradermal injection of the same filtrate. These changes are limited to the nodes served by the lymphatic injected or to those furnishing the lymphatic drainage for the injected skin site. By either method the initial or preparatory injection of filtrate reaches the lymph nodes through one or more of its afferent lymphatics, and similar lesions are produced in the nodes.
The lesions consist of hemorrhages recognizable by gross and microscopic examination. The capillaries and veins are congested and thrombosed. Their endothelial cells are swollen. Arterioles are generally little affected. Though hemorrhages and thromboses are usually seen together in the nodes, they have been observed occurring independently. They are both probably secondary to endothelial changes. The lesions are not dependent on the amount of preexisting inflammation in the nodes.
Endothelial changes, hemorrhages and thromboses were usually noted in the regional nodes when positive Shwartzman reactions had been elicited in prepared skin by intravenous injection of the bacterial filtrate. However, these lesions in many instances were observed under similar conditions in these nodes even when the Shwartzman reaction in the skin was negative. It appears that lymph nodes are more susceptible to the production of the Shwartzman phenomenon than the skin sites which they drain.
A single intralymphatic or intradermal injection of the bacterial filtrates used in this study, even in high concentrations, does not produce in adjacent lymph nodes the characteristic changes noted when this preparatory injection is followed by a subsequent intravenous injection of the filtrate.
Single intravenous injections also are not productive of hemorrhage and thrombosis in lymph nodes.