HP and Sepsis: Therefore, we performed a second Hp sepsis study in which we addressed two critical questions: (1) in a model of severe and rapidly lethal bacterial septic shock secondary to S. aureus pneumonia, would Hp therapy have enough time to provide beneficial effects by reducing the availability of CFH; and (2) in a model of less severe sepsis with lower lethality, could the high levels of CFH produced by transfusing older RBCs result in toxicity from the circulation of large numbers of CFH-Hp complexes [29]?