In TTP against ADAMTS 13, the vWF cleaving protease and in the DEAP-HUS (Deficient for CFHR1 and CFHR3 proteins and autoantibody positive) group against the major complement regulator Factor H. Autoantibodies in MPGN are termed C3 Nephritic Factor (C3NeF) and are directed against a neoepitope of the complement C3 convertase C3bBb.