MICROSCOPIC POLYANGIITIS AFTER INFLUENZA VACCINATION

We describe a case of microscopic polyangiitis involving skin and join ts after influenza vaccination. Titers of antiinfluenza A antibody wer e markedly elevated in synovial fluid (SF) relative to those in serum. Antiinfluenza B antibodies were not present in SF but were present in serum, suggesting a reaction specifically involving antiinfluenza A a ntibodies localized to the affected joint. A review identified 16 othe r cases of vasculitis after influenza vaccination. The cases reclassif ied according to the Chapel Hill diagnostic criteria identified multip le forms of vasculitis including 7 other cases of microscopic polyangi itis. Three patients had similar illnesses after previous influenza va ccination or influenza-like illness. As in our case 11 cases resolved without recurrence, While this does not provide conclusive evidence th at the vaccination caused the vasculitis, together with the serologic data we present it supports this hypothesis.