Fulminant meningococcemia in a child with hereditary deficiency of the seventh component of complement and proteinuria.

A previously healthy 14-year-old boy presented with fulminant meningococcemia. He was found to have a total deficiency of C7. His serum totally lacked bactericidal activity against Neisseria meningitidis. Addition of purified C7 restored the serum hemolytic and bactericidal activity. Susceptibility to disseminated Neisseria infections has previously been reported in 3 patients with C7 deficiency, as well as in a few patients with deficiency of C5, C6 and C8. These findings emphasize the importance of intact complement mediated bactericidal activity in host defense against disseminated Neisseria infections. Evaluation of the complement system in individuals with Neisseria infections appears mandatory.