Anti-CTLA-4 therapy is associated with a high risk of autoimmune toxicity that can be unpredictable and severe such as colitis [20], and all forms of anti-CTLA and anti-PD1 therapy are associated with a small but real risk of irreversible toxicities such as neurologic toxicities and type-1 diabetes mellitus [21]. This evidence concerns the gene CTLA4 and diabetes mellitus.