CTLA4 and clostridium difficile infection: Interestingly, anti-CTLA4 mAbs (ipilimumab or tremelimumab), alone or anti-CTLA4 mAb with anti-PD1/PDL1 mAb combinations, were the causative agents in the cases of panhypophysitis, while isolated CDI was related to treatment with an anti-PD1/PD-L1 mAb.