IL4 and hemophagocytic syndrome: For blood inflammatory indicators, lower levels of procalcitonin (PCT) and Ferritin were observed in non-HLH patients than HLH patients (P = 0.027 and 1.24E-10, respectively), while no significant differences were found in C-reactive protein (CRP), interleukin-2, interleukin-4, interleukin-6, interleukin-10, tumor necrosis factor (TNF-α) and interferon (IFN).