CD4 and psoriasis: To assess the stimulatory capacity of B cells further, we separated peripheral blood mononuclear cells (PBMC) of HLA-C*06:02- or HLA-C*06:02+ healthy individuals (each n = 3) or HLA-C*06:02+ psoriasis patients (n = 4) by fluorescence activated cell sorting into B cells, CD4+ or CD8+ T cells, natural killer (NK) cells, monocytes and plasmacytoid dendritic cells (PDCs) using the strategy shown in Figure S2.