IL6 and hemophagocytic syndrome: As hypercytokinemia plays a key role in HLH, we have conducted serum Th1/Th2 cytokine determination by flow cytometry in pediatric patients with HLH since 2005 and reported that the cytokine pattern with significantly increased levels of interferon (IFN)-γ and interleukin (IL)-10 combined with a slightly increased IL-6 level was highly specific for childhood HLH (2).