TPH2 and systemic lupus erythematosus: These results imply that Tph1 cells are mainly regulated by CXCR3−CXCL9/10/11 axis, and partially by CCR2-CCL2 axis and CCR5-CCL3 axis, while Tph2 cells are predominantly regulated by CX3CR1-CX3CL1 axis in SLE.