Notably, we found an upregulation of costimulatory genes such as ICOS and TIGIT in Tph/Tfh cells from cutaneous lupus patients compared with their healthy control counterparts, and we further noted an upregulation of HLA-DRA and the transcription factor MAF, which has been demonstrated to promote Tph/Tfh cell function (Figure 2F; ref. 4). Here, TPH1 is linked to systemic lupus erythematosus.