Long-term Observation of the Serum Level of Anti-influenza Antibody Titers in Patients with Rheumatoid Arthritis on Receiving Vaccination with Identical Strains in the 2010 to 2012 Season

Aims: Influenza vaccination is effective in patients with rheumatoid arthritis (RA), although the humoral immune response to influenza vaccine is weak with some kinds of strain in RA patients having biologics. This study’s purpose is to investigate the immune response in RA patients who are weak at a humoral response to the vaccination, because we assume CD4+ T cells already recognize the epitope of influenza viral antigen presented by antigen-presenting cells, while the humoral response is not yet sufficient.

Study Design: Observational study.

Place and Duration of Study: Department of Japanese Oriental Medicine, Gunma Central & General Hospital (GCH), between October 2010 and February 2012.

Methodology: The strains of influenza vaccine in 2011-2012 were the same as those in 2010-2011 in Japan. Therefore, we investigated whether booster effects exist in the 2nd season compared with the response in the 1st season. In 38 RA patients (m/f: 2/36; age:60.4+/-13.7 mean+/-SD), we monitored the change in the serum level of anti-influenza antibody titers for 2 years.

Results: Booster effects were observed in the A/H3N2 strain; however, those effects were not observed in the A/H1N1 and B strains. There was no difference in the B strain at the baseline and at 4 weeks later, respectively, between 2010 and 2011. Titer’s fold in 2011 was not higher than that in 2011 in the 5 RA patients treated with biologics.

Conclusion: The interaction between CD4+ T cells and B cells may be variable with each strain among influenza vaccine. The clinical efficacy of influenza vaccination with the B strain against RA patients having biologics may be not clear until further observational studies are developed concerning incidence rate of each strain.