Alternatively, when the CS is caused by macrophage activation syndrome (MAF), the serum levels of interleukin 18 are elevated, while CS due to HLH is often characterized by elevated levels of TNF-a, interferon γ (IFN-γ), interleukin 1 (IL-1), IL-4, IL-6, IL-8, IL-10, IL-18, CXCL9, and CXCL10 [1]. Here, IL4 is linked to Cowden syndrome 1.