The frequency of CD69+, Granzyme B+ and IFNγ+ CD8 T cells in psoriasis patients was significantly lower following anti-CD3/CD28 stimulation (p<0.0005) (Figure 3B), suggesting downregulated TCR-dependent activation and impaired Tc1 cytokine production in CD8 T cells from psoriasis patients. This evidence concerns the gene CD28 and psoriasis.