Figure 3 shows that the serum levels of IL-33 in healthy controls (28.1 ± 56.0 pg/mL) were significantly lower than those in IG before therapy (43.4 ± 29.0 pg/mL) and after therapy (47.3 ± 36.6 pg/mL) and WG after IVIG (78.0 ± 143.7 pg/mL) (P < 0.05) (Figure 3(a)). Here, IL33 is linked to granulomatosis with polyangiitis.