IL17A and rheumatoid arthritis: At the microscopic molecular level, RA-Cold-related genes was mainly involved into amino acids (phenylalanine, tryptophan) metabolic pathway and IL-17 signaling pathway; while the development and progression of RA-Hot were mainly regulated by sphingolipid metabolism, glutamine metabolic pathway, NLRP3 and VEGF angiogenesis signal pathway.