The percentage of Th17 cells in the peripheral blood of EGPA patients at onset and remission was significantly positively correlated with the serum ICAM-1 level (P < 0.05, r = 0.37) (Fig. 5d) and inversely correlated with the serum VEGF level (P < 0.05, r = – 0.40) (Fig. 5f), but it was not correlated with the serum VCAM-1 level (NS, r = 0.18) (Fig. 5e). This evidence concerns the gene ICAM1 and eosinophilic granulomatosis with polyangiitis.