[Recurring meningococcal meningitis in hereditary C 5 deficiency].

Inherited deficiency of the 5th complement component (C5) was the cause of recurrent meningococcal meningitis in a woman aged 20 years. Familial investigations confirmed an autosomal co-dominant type of inheritance for the defect. Whereas additional loss of chemotaxis only exists with a genetic defect in C5 complement, bacteriolytic activity of serum is lacking in all genetic defects of the terminal complement components C5 to C8. An intact bacteriolysis, however, is necessary for resistance against Neisseria meningitidis and Neisseria gonorrhoeae. Neisseria infections, particularly recurrent meningococcal meningitis or disseminated gonococcal infections, suggest the presence of a congenital or acquired deficiency in one of the complement components C5 to C8.