Recurrent meningococcal meningitis due to partial complement defects and poor anti-meningococcal antibody response.

An otherwise healthy young man had three episodes of meningococcal meningitis within three years. The last episode was caused by group A, and occurred four weeks after the patient received group A vaccine, thus representing one of the very few failures of this vaccine. The specific susceptibility to meningococcal infections was connected with half-normal levels of several components of the complement system (C3, C4, C9, factor B, properdin), and reduced antibody responses to group A and group C meningococcal polysaccharides, but not to several other polysaccharide or protein antigens.