CD4 and psoriasis: In addition, 84.7% of CD161+ T-cell cluster cells expressed CXCL13, while only 1.6% of CD8+ T-cell cluster cells, 2.5% of CD4+ T-cell cluster cells, and 0.6% of Treg cluster cells expressed CXCL13 in pretreatment psoriasis lesional skin (Figure 4B).