CTLA4 and hyperinsulinemic hypoglycemia, familial, 4: A compelling case study by Giulia Angelino et al. [55] described the successful use of abatacept in a 17-year-old patient with CTLA-4 deficiency, who presented with gastric cancer along with severe immune dysregulation, including early-onset inflammatory bowel disease, type 1 diabetes, and polyautoimmunity.