Human deficiency of the sixth component of complement in a patient with meningococcal meningitis and no haemostasis abnormality.

A case of human complete C6 deficiency is reported.
The patient, a 31 year old white male, was seen on the occasion of an isolated episode of meningococcal meningitis.
Serum complement hemolytic and bactericidal activities were lacking and could be restored to normal by addition of appropriate amounts of purified C6. No hemostatic abnormalities were observed.. 
