CXCR5 and systemic lupus erythematosus: CXCR5-PD-1hi Tph cells cocultured with class-switch memory B cells in the presence of TGF-β3 revealed much class-switch memory B cells differentiated into plasmocytes and high expression of IgG and IgM, suggesting that TGF-β3 regulates differentiation and function of Tph-like cells in lupus (112).