Development of a pharmaceutical apotransferrin product for iron binding therapy.

High-dose chemotherapy of patients with haematological malignancies results in extracellular iron accumulation and appearance of non-transferrin-bound iron, which is thought to predispose the patients to septic infections and contribute to organ toxicity. We describe the development of a human plasma-derived apotransferrin product for iron binding therapy. The product is purified from Cohn fraction IV of human plasma by two ion exchange chromatography steps and ultrafiltration. The process comprises solvent detergent treatment as the main virus inactivation step and 15 nm virus filtration and polyethylene glycol precipitation as removal steps for physico-chemically resistant infectious agents. Product characterization by electrospray and MALDI-TOF mass spectrometry indicated no other chemical modifications than N-linked glycan chains and disulphide bonds, except minor oxidation. The purity of the product was more than 98%, main impurities being IgG, IgA and hemopexin. The product had intact iron binding capacity and native conformation. A stable liquid formulation for the finished product was developed. The product has proved safe and well tolerated in early clinical trials in iron binding therapy.

Evidence for a role of hydroxyl radical in immune-complex-induced vasculitis.

Previously it was shown that tissue injury occurring in acute immune-complex-induced vasculitis, which is complement and neutrophil-dependent, is significantly attenuated by the presence of catalase, suggesting the pathogenic role of H2O2 generated from activated neutrophils. We now show that significant protection is also afforded by pretreatment of animals with apolactoferrin , a naturally occurring chelator of iron. Iron-saturated lactoferrin is devoid of protective effects. Deferoxamine mesylate, a synthetic iron chelator, also has protective effects. Infusion of ionic iron, especially Fe(III), potentiates the tissue injury. Significant protection from tissue injury is also produced by treatment of rats with dimethyl sulfoxide, a potent hydroxyl radical scavenger. Morphologically, animals treated with these protective interventions show the influx of neutrophils into sites of immune complex deposition, but there is markedly attenuated edema, little or no hemorrhage, and little evidence of endothelial cell injury, in contrast to the findings in nonprotected animals. These data support the suggestion that immune-complex-induced injury may be linked to generation of H2O2 from activated neutrophils and the subsequent conversion of H2O2 to the hydroxyl radical.