Radioimmunoassay and opsonic antibody responses to pneumococcal capsular polysaccharide vaccine in serum and ascitic fluid of cirrhotic patients.

Pneumococcal capsular polysaccharide vaccine was administered to 19 cirrhotic patients and to 25 control subjects. Radioimmunoassay antibody concentration and opsonic titers (OT) were measured in sera and ascites collected before and 3 to 4 weeks after inoculation. The geometric mean antibody concentrations in prevaccination sera from the cirrhotic patients were significantly increased to types 3, 4, 7F, 8, 9N, and 12F antigens, and in postinoculation sera their geometric mean antibody concentration was increased to types 3, 9N, and 12F antigens. OT to Streptococcus pneumoniae type 3 correlated with the radioimmunoassay antibody concentration in postinoculation sera. Of 14 cirrhotic subjects, 3 had OT of greater than or equal to 4 in prevaccination sera, and the highest OT and radioimmunoassay antibody concentration were observed in postinoculation specimens from this group. Antibody and OT against S. pneumoniae type 3 were also observed in ascitic specimens. These data suggest that cirrhotic subjects respond to pneumococcal capsular polysaccharide with antibodies in both serum and ascitic fluid. However, the protective efficacy of this antibody response must be assessed by larger prospective studies.