Autoimmune response following annual influenza vaccination in 92 apparently healthy adults

Objective To evaluate the possibility of autoimmune responses following annual influenza vaccination in a large cohort of apparently healthy adults. Methods Autoantibodies including antinuclear antibodies (ANA), anticardiolipin antibodies (aCL), anti-β2-glycoprotein I antibodies (anti-β2-GPI), lupus anticoagulant (LA) and anti-extractable nuclear antigen antibodies (anti-ENA) were determined in 92 healthy adult subjects, staff at the University Childrenʹs Hospital Ljubljana. Blood samples were taken from each participant before the vaccination, 1 month and 6 months after the annual influenza vaccination. Results Before the influenza vaccination, 26% of participants were positive for ANA, 16% for aCL, 7% for anti-β2-GPI, 2% for LA and 1% for anti-ENA. There were no statistically significant differences in the percentage of positive ANA, aCL, anti-β2-GPI, LA and anti-ENA before, 1 month and 6 months after the vaccination. One month after the vaccination 24% of participants demonstrated changes in the levels of autoantibodies including 15% of participants with increased level of autoantibodies or appearance of new autoantibodies. Six months after the vaccination 26% of participants demonstrated changes in the levels of autoantibodies including 13% of participants with increased level of autoantibodies or appearance of new autoantibodies. Persistently elevated levels of autoantibodies were observed in 7 (8%) participants and 2 showed progressively increased levels of IgM aCL or IgA anti-β2-GPI, respectively. Eleven participants had a transient increase in autoantibodies. Discussion Influenza vaccination in general did not alter the percentage of healthy adults with positive autoantibodies. Transiently or persistently increased levels of autoantibodies or appearance of new autoantibodies was demonstrated in up to 15% of apparently healthy adults after the influenza vaccination.