Vaccination is suggested to be less effective in SLE, especially in the background of azathioprine treatment, although measurement of antibody titers can only indirectly assess the efficacy of vaccination [2] . Latest studies supported that seroprotection after a single vaccination in SLE patients was significantly reduced compared to healthy controls [16] . The presented patient was vaccinated against seasonal influenza but not against H1N1 virus. Although recent reports suggest that CD8+ T cells are able to cross react with H1N1 virus, they are functionally impaired [17] .