Table 3.

TMAs other than TTP

Disorder	Pathophysiology	ASFA category for the role of TPE (see Table 4)
TMA–Shiga toxin mediated	Direct endothelial damage with apoptosis due to effects of Shiga toxin	Presence of severe neurologic symptoms, III
		Absence of severe neurologic symptoms, IV
TMA–complement mediated	Endothelial damage from unregulated complement activation resulting from the development of anti–factor H autoantibodies or mutations leading to abnormal complement regulatory proteins or abnormal complement factors	Complement factor gene mutations, III
		Factor H autoantibodies, I
		MCP mutations, III
TMA–hematopoietic stem cell transplantation associated	Endothelial damage due to infection, chemotherapy, radiation therapy, or graft-versus-host disease due to transplant. Of note, a significant percentage of affected individuals may have complement regulatory pathway mutations	III
TMA–drug associated	Mechanism varies depending on drug and includes direct endothelial damage as well as the development of ADAMTS13 autoantibodies	Depending on drug, I, III, or IV
TMA–malignancy associated	Activation of coagulation by tumor tissue factor expression. Possible complement regulatory pathway mutations	NC
TMA–Streptococcus pneumonia associated	Exposure of normally hidden endothelial antigens by bacterial neuramidase resulting in complement mediated endothelial damage	III
TMA–coagulation mediated	Mutations in DGKE, plasminogen, and thrombomodulin resulting in thrombosis and complement activation	III
HELLP syndrome	Mutations in alternate complement pathway regulatory elements	Postpartum, III
		Antepartum, IV

DGKE, diacylglycerol kinase-ε; HELLP, hemolysis, elevated liver enzyme levels, low platelet counts; NC, not categorized.