IL17A and COVID-19: Through the method of NP, the above part of the study analyzed the common action targets and regulatory signaling pathways of four diseases: COVID-19, RA, AS and GA, and discussed IL-17 signaling pathway and TNF signaling pathway, which are closely related to viral infection and inflammatory response, indicating that the regulation of these two signaling pathways commonly used in the treatment of RA, AS and other diseases can also affect the pathogenesis of COVID-19.