Bone marrow transplantation in the rat. II. Quantitation of cellular infiltrates in parenchymal target organs in acute graft-versus-host disease.

We have analysed the cytological structure of inflammation in the different parenchymal target organs during acute graft-versus-host disease after bone marrow transplantation in the rat. Inflammation (recovery of increased numbers of white cells) was recorded in the liver, skin, and lungs of the allograft recipient compared with the syngeneic graft recipient from day 5 onwards, accompanied by reduced recovery of inflammatory cells from the gut. The major cytological manifestation of the disorder was an increase in the total number of blast cells, large granular lymphocytes (LGL), and lymphocytes in the liver and skin, and of the number of blast cells and LGL in the lung. At the same time, a depletion of LGL and lymphocytes was recorded in the blood, suggesting migration of these cell components to the site of inflammation.