Tph cells are CXCR5-PD-1hi memory T cells, produce high levels of IL-21 and CXCL13, like Tfh cells, and are found in elevated numbers in blood of pSS patients, and in the salivary glands of pSS patients with GCs in their gland tissue (18–20). Here, CXCR5 is linked to peeling skin syndrome.