CTLA4 and hemophagocytic syndrome: Disorders that fall into this category include: hemophagocytic lymphohistiocytosis (HLH), autoimmune lymphoproliferative syndrome (ALPS), immunodysregulation polyendocrinopathy enteropathy X-linked (IPEX), autoimmune polyendocrinopathy candidiasis and ectodermal dystrophy (APECED), and CTLA4 haploinsufficiency [19, 33–36].