DETECTION OF C-POLYSACCHARIDE IN SERUM OF PATIENTS WITH STREPTOCOCCUS-PNEUMONIAE BACTEREMIA

Aim-To investigate the fate of Streptococcus pneumoniae C-polysacchari de antigen in serum in patients with S pneumoniae bacteraemia. Method- In vitro dissociation experiments were performed to demonstrate that C -polysaccharide was masked by ligands in normal and acute phase serum. Serum samples from 22 patients with S pneumoniae bacteraemia were tre ated to dissociate immune complexes and then tested for C-polysacchari de by enzyme linked immunosorbent assay (ELISA). Results-C-polysacchar ide antigen was masked in normal and acute phase serum but could be re leased by EDTA treatment and detected by ELISA. Antigen was found in s ix patients ranging in concentration from 2.5 to 200 ng/ml. Patients w ith detectable antigen were more likely to die than those in whom anti gen was not detected. Conclusion-This study demonstrates that C-polysa ccharide antigen commonly circulates in patients with S pneumoniae bac teraemia but its presence is masked by ligands present in serum.