Comparative immunopathologic studies of thrombotic thrombocytopenic purpura, hemolytic-uremic syndrome and disseminated intravascular coagulation.

The vascular lesion of thrombotic thrombocytopenic purpura was characterized by two distinct types of changes in the arteriole of the heart and brain: (1) multiple incomplete vascular occlusions due to the subendothelial deposits composed of a homogeneous fibrin fibrinogen-like substance and platelets without the formation of polymerized fibrin; (2) vascular wall thickening due to the intramural granular deposits of IGM and beta 1C. A patient with hemolytic-uremic syndrome 9 days after the onset of the disease, exhibited (1) the formation of fibrin-thrombi in the glomerular capillary lumens, and (2) the granular deposits of IgM and beta 1C along the glomerular capillary walls and in the mesangium. In contrast, the case in which the symptoms subsided five weeks after the onset exhibited neither fibrin-thrombus formation nor the deposits of IgM and beta 1C in the glomeruli. The vascular lesions of disseminated intravascular coagulation accompanied by pancreas carcinoma was located mainly in the capillaries, and were characterized by the formation of numerous fibrin-thrombi. Although the glomeruli contained numerous thrombi, there was neither endocapillary proliferation nor deposits of immunoglobulins and complement components.