Among actors of the cytokine storm, varying levels of interleukin-17A (IL-17A) were reported in LCH patient plasma (8, 21, 29–33), likely arising from circulating monocytes, as well as LCH-DCs and their derived giant cells inside granulomas (8, 29, 34, 35). The gene discussed is IL17A; the disease is Langerhans cell histiocytosis.