CTLA4 and clostridium difficile infection: In five cases, ICI-related CDI was diagnosed in the context of a panhypophysitis induced by ipilimumab (an anti-CTLA4 monoclonal antibody, anti-CTLA4-mAb): in three of them, ipilimumab was administered as a single agent (20–22), while in the other cases ipilimumab was administered in combination with nivolumab (an anti-PD1 monoclonal antibody, anti-PD1-mAb) (23, 24).