Hemolysis, free hemoglobin toxicity, and scavenger protein therapeutics

Blood. 2022 Oct 27;140(17):1837-1844. doi: 10.1182/blood.2022015596.


During hemolysis, erythrophagocytes dispose damaged red blood cells. This prevents the extracellular release of hemoglobin, detoxifies heme, and recycles iron in a linked metabolic pathway. Complementary to this process, haptoglobin and hemopexin scavenge and shuttle the red blood cell toxins hemoglobin and heme to cellular clearance. Pathological hemolysis outpaces macrophage capacity and scavenger synthesis across a diversity of diseases. This imbalance leads to hemoglobin-driven disease progression. To meet a void in treatment options, scavenger protein-based therapeutics are in clinical development.

MeSH terms

  • Haptoglobins / metabolism
  • Haptoglobins / therapeutic use
  • Heme / metabolism
  • Hemoglobins / metabolism
  • Hemolysis*
  • Hemopexin*
  • Humans


  • Hemopexin
  • Hemoglobins
  • Haptoglobins
  • Heme