Patients with clinically active vasculitis had evidence of endothelial injury, with an increased median CEC count of 88 (8–420) cells/ml, and systemic inflammation as indicated by a median ESR of 73 (11–137) mm/h and a CRP of 18.5 (5–270) mg/L; for children with inactive disease median CEC count was 16 (0–40) cells/ml, median ESR was 3 (3–37) mm/h, and median CRP was 5 (5–16) mg/L. This evidence concerns the gene CRP and vasculitis.