title: Recurrent meningococcal meningitis with absence of the sixth component of complement: an evaluation of underlying immunologic mechanisms.
abstract: A 51/2-year-old black girl with recurrent meningococcal meningitis and absence of the sixth component of complement (C6) is reported. To explore the pathogenesis of recurrent neisserial infections in C6 deficiency, a detailed analysis of her immune competence was conducted. Her serum had normal chemotactic, opsonic, alternative complement pathway, and specific antibody activity, but lacked complement-mediated bacteriolytic activity. In addition, her C6-deficient serum was indistinguishable from normal serum in a complement-dependent assay of phagocyte bactericidal activity. Absent bacteriolysis remains the only consistent defect associated with recurrent neisserial infections and absence of one of the late-acting complement components.
mesh_terms: D001770:Blood Bactericidal Activity; D002675:Child, Preschool; D003183:Complement C6 / Q000172:deficiency*; D005260:Female; D006461:Hemolysis; D006801:Humans; D007121:Immunocompetence; D008585:Meningitis, Meningococcal / Q000235:genetics / Q000276:immunology*; D010587:Phagocytosis; D012008:Recurrence
chemical_list: D003183:Complement C6