ANTI-PNEUMOCOCCAL ANTIBODY-RESPONSE IN NORMAL SUBJECTS - A METAANALYSIS

Background: The diagnosis of anti-polysaccharide antibody deficiency i s based on the presence of normal serum immunoglobulin levels and the lack of specific antibody response to polysaccharide antigens, such as the pneumococcal vaccine. However, a normal response to pneumococcal vaccine is not well defined. ''Modified meta-analysis'' was undertaken in an attempt to define the normal antibody response to pneumococcal vaccine. Methods: Studies identified by a MEDLINE search were selected Data of the normal control groups, rather than the patient groups, we re collated for analysis.Results: Twenty-three studies fulfilled the s election criteria. Prevaccination antibody titers, postvaccination tit ers, and post- to prevaccination titer. ratios varied widely. On the b asis of weighted mean ratios, serotype 8 appeared to be the most antig enic. It appeared that normal subjects do not mount a response of even a twofold increase in antibody titer to all the serotypes present in the vaccine. Moreover; no minimal absolute antibody level that could b e of diagnostic value, either before or after vaccination, was evident . Conclusion: Response to pneumococcal vaccine among normal subjects v aries widely. Better designed and prospective studies are needed to de fine the parameters of a normal antibody response to pneumococcal vacc ine so that uniform guidelines of interpretation can be formulated.