Quantification of IgM and IgA Anti-Pneumococcal Capsular Polysaccharides by a New ELISA Assay: a Valuable Diagnostic and Prognostic Tool for Common Variable Immunodeficiency.

Purpose: Existing ways of assessing CVID patients at risk of pulmonary infections are not universally accepted. The need to identify additional prognostic factors allowed us to evaluate the anti-polysaccharide IgA and IgM responses in 125 CVID patients immunized with the 23-valent pneumococcal polysaccharide (PS) vaccine (Pneumovax®). Methods: We used a new anti-PS23 IgM and IgA ELISA assay, which evaluates a global response to all 23 polysaccharides contained in Pneumovax®. Results: Anti-PS23 IgM and/or IgA antibodies were detectable in a minority of CVID patients. Antibody responses were correlated to B cell subpopulations and serum immunoglobulin concentrations. The non responders had a higher incidence of pneumonia and bronchiectasis and responders had the lowest incidence of respiratory complications. Conclusions: This new ELISA assay allows for studying vaccine response in patients on Ig replacement therapy. This test also is an additional method of evaluation of specific antibody responses representing a valuable contribution to identify prognostic marker in CVID patients. [ABSTRACT FROM AUTHOR]