The systemic form is typically acute, consisting of the classic triad of thrombocytopenia, microangiopathic hemolytic anemia with increase in lactate dehydrogenase, reduced haptoglobin, and schistocyte formation, and acute kidney injury (AKI); this has been described in 18–62% of patients with PT-TMA (19, 21, 25, 26). This evidence concerns the gene HP and acute kidney injury.