CD4 and pemphigus: To further analyze skin TLSs in pemphigus, we enrolled patients with pemphigus with chronic bullae persisting for more than 4 months, obtained punch biopsies of the chronic lesions, and carried out immunohistochemical studies for CD20, CD138, CD4, and PNAd to identify TLSs (Figure 1B and Supplemental Table 1).