The rate of formation and the composition of lymph from primary and secondary renal allografts.

Abstract

Summary The rate of formation and composition of lymph from renal allografts has been studied in normal and sensitized ewes and related to the histopathological appearance of the graft at various times during its life. Analysis of the volume of lymph being formed, its protein content, and the types and numbers of cells appearing in the lymph showed that pathological events within the graft were reflected closely in changes in the lymph. In first-set allografts large numbers of lymphocytes migrated from the blood into the graft. Many of these cells underwent blast transformation and left the graft by way of the lymph. During the first 24–48 hr the blood capillaries of the graft were very permeable to red cells and plasma proteins, but after this time the protein content of the lymph fell, the red cells disappeared, and the rate of lymph flow increased many-fold. This phase correlated with the appearance of lymphoid cell emboli in the small vessels of the graft. Around 160 hr there was a precipitous fall in lymph flow and the numbers of red cells and the protein content of the lymph rose. This terminal phase was related to the appearance of antibody in the blood and to the widespread destruction of the vasculature of the graft. Renal grafts rejected in an accelerated fashion produced significantly less lymph than first-set grafts. The permeability of the blood capillaries of grafts installed in sensitized recipients remained high throughout, and large numbers of red cells and polymorphonuclear leucocytes appeared in the lymph from the outset. When antibody was present in the blood of the recipient, the traffic of lymphocytes into the graft was greatly reduced and amounted to about 1–5% of the number of cells migrating through primary allografts. Although antibody had a pronouced effect on the migration of lymphocytes into the graft, it did not seem to affect the subsequent trans-formation of lymphocytes into blast cells, and the proportion of blast cells to lymphocytes was similar to that seen in primary grafts.