CD4 and melanoma: However, Ipilimumab-treated melanoma had lower ratios of Treg/CD4 T cells than the untreated, while Tremelimumab-treated patients had higher ratios of Treg/CD4 T cells.47 The lack of Treg depletion by Tremelimumab is expected as Tremelimumab is an IgG2 isotype, which is largely devoid of ADCC activity.