Compared with healthy volunteers, the levels of leukocytes, C-reactive protein (CRP), macrophage migration inhibitory factor (MIF) and vascular endothelial growth factor (VEGF) were significantly (p < 0.05) elevated in the patients with severe hemophilia A and were significantly higher in patients with joint bleeding than in nonbleeding patients (p < 0.05). The gene discussed is VEGFA; the disease is hemophilia A.