S100A12 and necrotizing vasculitis: To determine if common indicators of inflammation (blood cell counts, ESR, CRP, Hb) and S100A12 correlate with disease activity over the course of CPV, we analyzed a total of 117 serum samples obtained concurrent with clinical data from 56 children with systemic vasculitis; 48 samples were collected at times likely to correspond to high disease activity (diagnosis and flare), and 69 samples at follow up visits when disease activity should be reduced.