Immune phenotyping of CD4+ T-cells to identify the proportion of naïve (CD3+CD4+CCR7+CD45RA+; 48.0% in HCs, 58.4% in psoriasis, 51.6% in PsA), Central Memory (CM; CD3+CD4+CCR7+CD45RA-; 20.5% in HCs, 18.2% in psoriasis, 23.5% in PsA), Effector Memory (EM; CD3+CD4+CCR7-CD45RA-; 25.4% in HCs, 18.4% in psoriasis, 25.5% in PsA), and Effector Memory cells re-expressing CD45RA (EMRA; CD3+CD4+CCR7-CD45RA+; 1.1% in HCs, 1.4% in PsA and 1.9% in psoriasis) subsets did not deliver differences between controls and patients with skin psoriasis or PsA (Supplementary Figures 1, 2; Supplementary Table 2). Here, CD4 is linked to psoriasis.