Kinetics of the long-term antibody response after meningococcal C vaccination in patients with juvenile idiopathic arthritis: a retrospective cohort study.

OBJECTIVES: The kinetics of the antibody response induced by meningococcal serogroup C (MenC) conjugate vaccination was analysed in patients with juvenile idiopathic arthritis (JIA) to assess their long-term protection against MenC disease.
METHODS: In The Netherlands, a nationwide catch-up campaign was performed in 2002 during which children aged 1-19 years, including JIA patients, received the MenC conjugate vaccination. From 127 JIA patients, IgG antibody concentrations against MenC-polysaccharide were determined by a fluorescent-bead-based immunoassay in 402 serum samples collected between 2002 and 2010. Using a hierarchical linear regression model, the 8 years course of MenC-specific antibodies was analysed in four age groups (13-19, 9-12.9, 5-8.9 and 1-4.9 years), and in patients starting with methotrexate or biologicals. In 65 randomly selected samples, the correlation of MenC-specific IgG concentrations with serum bactericidal assay (SBA) titres was assessed. MenC-specific IgG concentrations at 4.2 years after vaccination were compared with those of 1527 age-matched healthy controls.
RESULTS: MenC-specific IgG concentrations postvaccination were highest in patients aged 13-19 years at time of vaccination. Antibodies gradually waned over time in patients, but their estimated concentrations at 4.2 years postvaccination were similar to those measured in controls. MenC-specific IgG concentrations correlated well with SBA titres (r=0.72, p<0.001). By contrast with methotrexate, starting treatment with biologicals induced a trend towards accelerated decline of MenC-specific antibodies.
CONCLUSIONS: Persistence of MenC-specific IgG antibodies in JIA patients is similar to healthy controls, but treatment with biologicals may induce accelerated antibody waning, resulting in unprotected patients who may need revaccination.