Moreover, an altered peptide ligand (APL) derived from a CD4+ T cell epitope of human Hsp60 inhibited the course of murine arthritis, similarly to methotrexate (Lorenzo et al. 2017), and increased the percentage of Treg or downregulated the secretion of pro-inflammatory IL-17 in peripheral blood mononuclear cell cultures from RA patients (Barberá et al. 2016). The gene discussed is CD4; the disease is rheumatoid arthritis.