Recurrent meningococcal infections in a patient with congenital C5 deficiency.

A congenital C5 deficiency was the cause of recurrent meningococcal disease in a 27-year-old man. The lack of serum bactericidal activity accounts for the higher incidence and the different course of Neisseria infections in patients with a deficiency of the late complement components. Early antibiotic treatment and vaccination with a capsular polysaccharide meningococcal vaccine (A,C,Y,W-135) should be considered.