JAK2 and rheumatoid arthritis: Indeed, recent studies have demonstrated that calcitriol potently inhibits RANKL expression by suppressing RORγT and IL‐17 expression in Th17 cells16 and that this inhibitory effect can debilitate osteoclastogenesis through JAK‐2/STAT‐3 and p38 MAPK/NF‐κB signalling in rheumatoid arthritis.44