Immune response to influenza vaccine and pneumococcal polysaccharide vaccine under IL-6 signal inhibition therapy with tocilizumab

OBJECTIVES: To evaluate humoral immune response to influenza vaccine and polysaccharide pneumococcal vaccine in patients with rheumatoid arthritis (RA) or Castleman's disease (CD) during tocilizumab therapy. METHODS: Thirty-eight patients (28 RA and 10 CD) receiving tocilizumab and 39 RA patients receiving TNF inhibitors and/or synthetic DMARDs subcutaneously received a single dose of a split-virion inactivated influenza vaccine containing A(New Caledonia (NC):H1N1), A(Hiroshima (HIR):H3N2) and B(Malaysia (MAL)) strains. Twenty-one RA patients using tocilizumab also received 23-valent polysaccharide pneumococcal vaccine. Antibody titers were measured every 4 weeks for a total of 12 weeks after vaccination. RESULTS: In the tocilizumab group, seroprotective titers (40-fold or more) were obtained in 36/38(95%) for A(NC), 35/38(92%) for A(HIR) and 32/38(84%) for B(MAL). In the patients with baseline antibody titer < 40-fold, 11/11(100%), 7/8(88%) and 18/20(90%) patients showed four-fold or more increase in the titer from baseline to A(NC), A(HIR) and B(MAL), respectively. Patients using TNF inhibitors and/or DMARDs showed similar responses. Pneumococcal antibody titers increased at least two-fold in more than 9 of 12 serotypes, which continued for longer than 12 weeks in all the patients. CONCLUSION: Interleukin-6 (IL-6) blocking therapy with tocilizumab did not affect the humoral immune response to both influenza and pneumococcal vaccines.