The expression levels of LXRA and SREBP1 displayed different patterns between the IFP and SC in OA and RA patients, and the effects of concurrent or historical administration of MTX could serve as one of the reasons; this is because MTX was revealed to inhibit the amounts of inflammatory signals via the JAK1-STAT3 and JAK2-STAT5 transcriptional pathways in human macrophage cell lines (28, 29). Here, JAK2 is linked to rheumatoid arthritis.