Figure 1

CpG-B induces ANCA production from vasculitis patients in vitro. PBMCs isolated from patients with active ANCA associated vasculitis, 5 PR3⁺ and 5 MPO⁺ ANCA patients, were cultured with CpG-B and IL-2. Each patient assay was paired with a healthy control. After 12 days of culture, supernatants were harvested. IgG concentration and supernatant reactivity to either PR3 or MPO was measured by ELISA. The amount of IgG detected in the supernatants was of 5.5 ± 2.2 μg mL^-1 in the patients compared to 4.1 ± 1.2 μg mL^-1 in the control group (A). Figure B shows the reactivity of the supernatants from PR3⁺ ANCA patients towards PR3 antigen. The difference against control individuals was highly significant (P = 0.0082). Figure C shows the reactivity of the supernatants from MPO⁺ ANCA patients towards MPO antigen. The difference was not significant (P = 0.072) although their supernatants showed a clear tendency towards higher reactivity compared to controls. There was no correlation between patients' serum ANCA titre at the time of the assay and their in vitro production of ANCA in response to CpG-B as shown in D (r² = 0.172).