Antineutrophil cytoplasmic antibody vasculitis associated with influenza vaccination.

BACKGROUND Administration of influenza vaccines has been associated with the development of autoantibodies and autoimmune rheumatic disease. PATIENTS We discuss 2 patients who developed antineutrophil cytoplasmic antibody-associated vasculitis (AAV) in temporal association with influenza immunization. AAV was diagnosed 2 and 4 weeks after immunization in these patients. Both patients had renal involvement with one requiring dialysis. Both patients were treated with cyclophosphamide and corticosteroids, and plasmapheresis was added to the immunosuppressive regimen in one patient with dialysis-dependent renal failure. Both patients achieved disease remission. The patient with initial dialysis-dependent renal failure reached end-stage renal disease. There are 6 previous cases of AAV in the literature described in temporal association with administration of influenza vaccines. CONCLUSION A causal role of vaccines in AAV cannot be confirmed with these case reports. The temporality suggests that the influenza vaccine may be a triggering factor for induction of vasculitis in predisposed individuals. We review the literature on reported cases of AAV following influenza vaccine administration and discuss possible mechanisms for influenza vaccine-associated AAV.