Thirty-seven patients with rheumatoid arthritis being treated by biological agents (infliximab 20 patients, etanercept 17 patients) received 23-valent pneumococcal polysaccharide vaccine intramuscularly. The adverse events considered to be related to the vaccination and antibody responses to the 14-capsular polysaccharide antigens were examined. The frequencies and characteristics of vaccination-related adverse events in the present RA patients were similar to those observed in the clinical trials conducted for the drug approval in which the healthy volunteers were vaccinated. The adverse events were also not different in their frequencies and severities between the 28 patients and 9 patients vaccinated by pneumococcal polysaccharides and influenza vaccines on the same day and different day respectively. After the pneumococcal vaccination, patients with rheumatoid arthritis showed significant antibody responses (more than two-fold increase of antibody titer) to all of the 14-polysaccharide antigens to which the specific antibodies were measured. The magnitudes of these antibody responses were lower in patients with rheumatoid arthritis than those reported in the original clinical trials. Between the RA patient groups treated by either infliximab or etanercept, differences in antibody responses to pneumococcal antigens were not observed.
    The results of the present study indicate that the vaccination to pneumococcal polysaccharides in rheumatoid arthritis patients do not results in the significant adverse events and although the maginitudes of specific antibody responses were lower than in healthy subjects, patients with rheumatoid arthritis produce significant amounts of the specific antibodies.