PRF1 and melanoma: CD4+ T cell lines established from all four patients from peripheral blood mononuclear cells (PBMCs) after ipilimumab therapy expressed granzyme B, perforin, and LAMP (CD107a) and were able to lyse autologous melanoma cells in a manner dependent on MHC class II recognition; analysis of lines established from longitudinal samples before or after ipilimumab from one patient demonstrated that the induction of cytolytic granzyme and perforin occurred only after ipilimumab therapy (Kitano et al., 2013).