In this study, we focus on the effect of TLR stimulation, in particular the stimulation of PBMCs by the TLR-9 specific ligand single-stranded DNA with CpG motifs, CpG oligodeoxynucleotide (CpG) as found in bacteria and viruses, to see if this agent might stimulate in vitro production of IgG ANCA from patients with ANCA+ vasculitis. This evidence concerns the gene TLR9 and vasculitis.