Cloaking antibodies are prevalent in complex infection and their removal restores serum killing.

Introduction: The complex encompasses a group of gram-negative opportunistic pathogens that cause chronic lung infections in people with cystic fibrosis. Distinct from other respiratory pathogens, causes a unique clinical disease in a subset of patients known as 'cepacia syndrome', fulminant pneumonia accompanied by bacteraemia and sepsis with a mortality rate of up to 75%. Due to the bacteraemia associated with this disease, the mechanisms that allow to resist the bactericidal effects of serum complement-depending killing are vital.