ABSTRACT
Nanocarriers, such as liposomes and nanoparticles, have been widely explored as promising delivery vehicles in modern pharmacotechnology. The interaction of liposomes with the immune system has contributed to the challenges in translation to clinical use. Complement activation per se cannot solely explain liposome-induced pseudoallergy; instead, it may be a trigger or contributing factor, but not the sole cause of hypersensitivity reactions in sensitive individuals. Surface functionalization of liposomes with methoxy-terminated Polyethylene glycol is supposed to substantially suppress/inhibit complement activation. Complement activation and hypersensitivity reactions (CARPA) and accelerated blood clearance phenomenon are considered two sides of the same coin, both being spin-off phenomena of a vicious cycle of complement activation by nanoparticles, antibody formation and antibody binding to the activator-accelerating complement activation. Patient pretreatment with anti-inflammatory and anti-allergic agents has been considered one of the most commonly applied approaches to prevent and/or reduce CARPA.
