Specific cytokine patterns in Epstein-Barr virusassociated hemophagocytic lymphohistiocytosis compared to Kawasaki disease in children

The aim of the study was to test whether the cytokine profile could be used as a marker to differentiate between Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) and Kawasaki disease (KD). A total of 70 hospitalized children with HLH and KD admitted to hospital for the first time from March 2017 to December 2021 were enrolled in this study. Fifty-five healthy children were enrolled as normal controls. All patients and normal controls were tested for the six cytokines including interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) by flow cytometry. IL-10 and IFN-gamma levels were significantly higher in children with EBV-HLH than in the KD, IL-6 was lower in EBV-HLH patients than in the KD. IL-10/IL-6 ratio, IFN-gamma/IL-6 ratio and IL10/IFN-gamma ratio in children with EBV-HLH were significantly much higher than children in the KD group. When the diagnostic cutoff values of IL-10, IFN-gamma, IL-10/IL-6 ratio and IFN-gamma/IL-6 ratio were >13.2 pg/ml, >71.0 pg/ml, >0.37 and >1.34, respectively, the sensitivity and specificity of the diagnosis of EBV-HLH disease were 91.7% and 97.1%, 72.2% and 97.1%, 86.1% and 100.0%, and 75.0% and 97.1%, respectively. Notably high IL-10 and IFN-gamma and moderately elevated IL-6 suggest the diagnosis of EBV-HLH, while high IL-6 levels with low IL-10 or IFN-gamma concentration would suggest KD. Additionally, IL-10/IL-6 ratio or IFN-gamma/IL-6 ratio could be used as an index to differentiate between EBV-HLH and KD.