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Answer 80 = [B] Factor H
Answer 81 = [B] Eculizumab
Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy characterized by intravascular hemolysis, thrombocytopenia, and acute kidney failure.
Hemolytic uremic syndrome (HUS) is one of the disease processes that belong to thrombotic microangiopathies (TMAs)
 Typical HUS (ie, STEC-HUS) follows a gastrointestinal infection with STEC
 aHUS is associated primarily with mutations or autoantibodies leading to dysregulated complement activation.
Note = Among the 30% to 50% of patients with aHUS who have no detectable complement defect, some have either impaired diacylglycerol kinase ε (DGKε) activity, cobalamin C deficiency, or plasminogen deficiency.
In aHUS, mutations have been reported in 5 central complement proteins [Factor H, MCP (CD46), Factor I, C3, Factor B]. Most of these mutations lead to impaired regulation of alternative pathway activation. Most commonly involved gene is of Factor H (25-30% of cases)
Historically, aHUS had a poor prognosis with about 50% of all patients progressing to end-stage renal disease (ESRD).
Prior to the introduction of eculizumab, plasma infusion or plasma exchange (PI/PE) was the standard of care by supplying the normal/functional complement inhibitory molecules, but they do not address the underlying pathology.
Eculizumab, a terminal complement inhibitor that binds to C5 with high affinity, blocks the generation of proinflammatory C5a and C5b-9. Approved in 2011 in the United States, it is the drug of choice for the treatment of aHUS; immediate treatment with eculizumab is strongly recommended when the diagnosis of aHUS is confirmed.