title: Laboratory diagnosis of specific antibody deficiency to pneumococcal capsular polysaccharide antigens.
abstract: BACKGROUND
  Measurement of postimmunization antibody response to pneumococcal capsular polysaccharide (caps-PS) is the standard method to identify deficiency of antipolysaccharide antibody production. However, no standardized criteria have been defined for classification of patients into responders or nonresponders to caps-PS.
  
  
  METHODS
  We vaccinated 37 healthy children and 39 healthy adults with Pneumovax and measured the anti-caps-PS antibody response to 5 serotypes. We also measured antipneumococcal antibody titers in 82 patients with increased susceptibility to airway infection. The ELISA was performed according to the 3rd-generation assay format.
  
  
  RESULTS
  The lower 5th percentile (cutoff) concentrations for the postimmunization antibody titer in healthy individuals were 0.67 mg/L, 0.45 mg/L, 0.46 mg/L, 0.31 mg/L, and 1.04 mg/L for serotypes 3, 4, 9N, 18C, and 19F, respectively. In 96% of healthy individuals, antibody responses higher than the cutoff concentration were seen for at least 3 of the 5 serotypes. Nine of 82 patients (11%) failed to mount an adequate antibody response for at least 4 of the 5 serotypes tested, whereas only 1 control (1.3%) failed to do so.
  
  
  CONCLUSIONS
  The cutoffs for antibody responses to caps-PS identified in this study appear useful for identifying individuals with an inadequate response to vaccine.
authors.affiliation: Laboratory Medicine, Immunology, University Hospital Leuven, Belgium.
authors.forename: Axel
authors.initials: A
authors.lastname: Jeurissen
authors.forename: Leen
authors.initials: L
authors.lastname: Moens
authors.forename: Marc
authors.initials: M
authors.lastname: Raes
authors.forename: Greet
authors.initials: G
authors.lastname: Wuyts
authors.forename: Luc
authors.initials: L
authors.lastname: Willebrords
authors.forename: Kate
authors.initials: K
authors.lastname: Sauer
authors.forename: Marijke
authors.initials: M
authors.lastname: Proesmans
authors.forename: Jan L
authors.initials: JL
authors.lastname: Ceuppens
authors.forename: Kris
authors.initials: K
authors.lastname: De Boeck
authors.forename: Xavier
authors.initials: X
authors.lastname: Bossuyt
mesh_terms: D000293:Adolescent; D000328:Adult; D000917:Antibody Formation; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D022242:Pneumococcal Vaccines / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D012141:Respiratory Tract Infections / Q000276:immunology / Q000517:prevention & control; D013296:Streptococcus pneumoniae / Q000276:immunology*
chemical_list: D022242:Pneumococcal Vaccines; D011135:Polysaccharides, Bacterial