IL17A and acquired polycythemia vera: Currently, drugs targeting TNF-α, IL-23, and IL-17 and signaling pathways such as JAK/STAT are effective in the clinical treatment of PV.[16] However, adverse reactions caused by biological agents have been frequently reported, such as serious infection, hepatitis B and C virus reactivation, interstitial pneumonia, drug-induced lupus erythematosus, etc. More clinical studies are needed on the safety of bio targeted therapy.[21] Moreover, it is expensive and not fully marketed and covered by medical insurance in China, so it is not a good choice for PV patients in China.