Type 1 IFN signaling has been shown to promote the differentiation of autoreactive, T-dependent, extrafollicular plasmablasts in a mouse model of SLE (74), and in vitro studies of human T cells demonstrate that IFN-α stimulation can induce CD4 T cell phenotypes consistent with Tph/Tfh differentiation (75). Here, TPH1 is linked to systemic lupus erythematosus.