title: [C2 deficiency discovered in pneumococcal meningitis].
abstract: BACKGROUND
  Congenital deficiencies of complement system proteins are rare. Patients with C2 deficiency have a high incidence of vascularitis syndromes. Most patients with this deficiency have no problems with increased susceptibility to infection, most commonly due to pneumococci, presumably because of the protective function of the alternative pathway.
  
  
  METHODS
  A 22 month-old girl was admitted because of acute meningitis and otitis. She had had 2 episodes of otitis media at the age of 1 year. Analysis of the CSF showed that this meningitis was due to pneumococcal infection. Recovery was complete after 15 days of antibiotic therapy. Total hemolytic complement activity (CH50) was low during the infection; one month later, the CH50 value was about zero as was C2, while C3 and C4 were normal. The patient was given polyvalent pneumococcal and anti-Haemophilus vaccines plus prophylactic penicillin G. Laboratory tests for systemic lupus erythematosus were negative.
  
  
  CONCLUSIONS
  A defect of complement function should be suspected in any patient with severe of recurring pyogenic infections. Complement disorders can be detected one month later by means of the relatively simple hemolytic complement assay.
authors.affiliation: Service de Pédiatrie B, Hôpital Saint-Vincent-de-Paul, Paris.
authors.forename: M
authors.initials: M
authors.lastname: Monfort-Gouraud
authors.forename: M A
authors.initials: MA
authors.lastname: Le Gall
authors.forename: F
authors.initials: F
authors.lastname: Nicot
authors.forename: J
authors.initials: J
authors.lastname: Badoual
mesh_terms: D003175:Complement C2 / Q000172:deficiency* / Q000276:immunology; D005260:Female; D006801:Humans; D007223:Infant; D008586:Meningitis, Pneumococcal / Q000276:immunology*
chemical_list: D003175:Complement C2
vernacular_title: Déficit en C2 découvert au décours d'une méningite à pneumocoque.