To further confirm the role of CD8+ TCM cells in psoriasis relapse and identify target cells of DHA, DHA-treated mice received exogenous CD4+ or CD8+ TCM cells on day 20, the beginning date of IMQ re-challenging, while others were administered with rIL-15 on days 0, 3 and 6 during initial IMQ priming, as depicted in Figure 4A. As shown in Figure 6F, we found that infusion of CD8+ TCM cells mostly reversed DHA-mediated reduction in the PASI scores on day 24, the peak time for skin lesions, whereas injection of CD4+ TCM cells failed do so. The gene discussed is CD4; the disease is psoriasis.