Abstract

TEXT In this issue, Zhang et al. of the Cleveland Clinic report on an interesting, and what we consider a critical, analysis of multianalyte pneumococcal antibody testing at three major reference laboratories in the United States ( 1 ). The determination of the immune response to pure polysaccharide, or conjugated polysaccharide, pneumococcal vaccination has become a critical part of the workup of patients suspected of having the whole spectrum of antibody deficiency diseases. These include patients with the most common immunodeficiency, common variable immunodeficiency, as well as individuals with less common but often quite serious IgG subclass deficiency (particularly, IgG2 deficiency), as well as what is known as “specific polysaccharide antibody deficiency.” These individuals fail to make antibody to pure polysaccharides even though their overall IgG, IgG subclasses, and responses to protein vaccines may be perfectly normal. The initial testing that led to licensing of the pure pneumococcal polysaccharide vaccine, as well as the initial Prevnar7 conjugated pneumococcal vaccine, was carried out mainly by employing enzyme-linked immunosorbent assay (ELISA) methodology to determine immune responses ( 2 , 3 ). We at ARUP Laboratories had a great deal of experience with the CDC-approved and FDA-standardized ELISAs ( 2 ,