Dysfunctional Properdin in a Dutch Family with Meningococcal Disease

DEVELOPMENT of systemic infections with Neisseria meningitidis can usually be ascribed to the absence of protective IgM or IgG antibodies, or to the presence of IgA antibodies that block serum bactericidal reactions.1 , 2 Studies of rare complement-deficiency states have drawn attention to the importance of the complement system as a mediator of host defense against infections with neisseria and other bacteria.3 , 4 Properdin is a component of the alternative pathway of complement. Reports from studies of fulminant meningococcal infections or single episodes of meningococcal disease in patients with properdin deficiency have suggested a potential role of the alternative pathway in complement-dependent resistance . . .