In vitro and in vivo properties differ among liquid intravenous immunoglobulin preparations

Objective To compare in vitro and in vivo biological and biochemical properties of five liquid intravenous immunoglobulin (IVIg) preparations licensed for therapeutic use in Europe. Methods ClairYg (R) was compared in a blinded manner to four other liquid IVIg preparations licensed in Europe (Octagam (R), Kiovig (R), Gamunex (R), Privigen (R)). Three batches of each preparation were tested, except for the IgG repertoires and the animal model. Results Levels of anti-A and anti-B antibodies were lower in ClairYg (R) (0.11/0.11) relative to a positive EDQM standard and Octagam (R) (0.11/0.08) than in other preparations (0.33-0.69/0.42-0.46). IgG in ClairYg (R) recognized 365 and 416 protein spots in HEp-2 cell and Escherichia coli protein extracts vs. 230-330 and 402-842 protein spots, respectively, for IgG in other preparations. IgA content (301 vs. 165-820 ng/mg of IgG), Factor XI and Factor XII antigen (0.46 vs. 0.85-2.40 mU/mg of IgG and 7.8 vs. 20.0-46.2 lU/mg of IgG) C1q binding (0.42 vs. 0.67-1.89 arbitrary units) and C5a uptake (0.41 vs. 0.45-0.66% of activation) were lower in ClairYg (R) than in other preparations. Finally, intravenous infusion of ClairYg (R), Gamunex (R) and Privigen (R) had no major effect on arterial blood pressure in spontaneously hypertensive rats. Conclusions Our results evidence some differences in the biological and biochemical properties among licensed liquid IVIg preparations.