Systemic vasculitis associated with alphal-antitrypsin deficiency.

We describe a rare case of systemic vasculitis associated with alpha1-antitrypsin (alpha1-AT) deficiency. Mutational analysis of the alpha1-AT gene in this patient revealed a homozygous alpha1-AT Mnichinan variant. Alpha1-AT possesses broad-spectrum inhibitory activity against many serine proteases, including human neutrophil elastase, to help maintaining the crucial balance between proteases and protease inhibitors. The increase in free protease activity in the context of alpha1-AT deficiency may induce exacerbation of the vasculitis. This serious genetic defect severely affects the balance between a protease and a protease inhibitor at the pathological site.