CD4 and systemic lupus erythematosus: To examine phenotypes specific to skin-infiltrating T cells, we sorted CD4+ and CD8+ T cells from lesional dorsal skin of 20-week-old MRL/MpJ-Faslpr/J (MRL/lpr) SLE-prone mice, separating the tissue-resident cells from circulating cells (Supplemental Figure 1; supplemental material available online with this article; https://doi.org/10.1172/jci.insight.166076DS1).