Fig. 2

Plasma C4d levels are increased in active ANCA-associated vasculitis (AAV) patients with a diagnosis of granulomatosis with polyangiitis (GPA) or anti-proteinase 3 (PR3) ANCA positivity. C4d (a), C4 (b), C4d/C4 ratio (c) and sTCC (d) levels in anti-myeloperoxidase (αMPO, n = 16) positive versus anti-PR3 (αPR3) autoantibody positive (n = 24) AAV patients with active disease. C4d (e), C4 (f), C4d/C4 ratio (g) and sTCC (h) levels in GPA patients (n = 27) versus microscopic polyangiitis (MPA, n = 13) patients with active disease. The grey ranges depict the normal reference intervals. Data are presented as medians with 25–75% quantiles plus min to max whiskers, and significance was calculated using the Mann–Whitney U test. **p < 0.01