Lymphatic visualization during renal transplant rejection.

Intrarenal microlymphatic filling was observed during a microangiographic and histologic study of unmodified canine allograft rejection. The extent of lymphatic visualization was correlated with the pathophysiologic state of the allograft. An example of renal lymphatic visualization following arterial perfusion of a human specimen is also presented. During early rejection, as microvascular and histologic alteration became more severe, there was prominent visualization of lymphatics. However, in late rejection, as cortical necrosis developed, lymphatic filling was less evident. Lymphatic visualization following arterial perfusion during rejection depends on progressive loss of microvascular integrity, contrast extravasation and subsequent filling of lymphatics which are acting as an alternate route of drainage for the excess interstitial edema present due to immune injury.