Significance of serum Th1/Th2 cytokine levels in underlying disease classification of childhood HLH.

Abstract Object Goal of this research was to investigate values of serum cytokines in childhood HLH with different triggers, with the expectation to find secretion spectrum of 5 main types of underlying diseases. Method 118 newly diagnosed HLH were included, and serum concentrations of 6 cytokines were tested before treatment began. Absolute cytokine levels and ratios between them were then studied in the HLH groups collectively and separately Results In general, IFN-γ, IL-10 and IL-6 showed differences among 5 HLH groups. Specifically, relative levels of these three cytokines to each other were meaningful in distinguishing 4 types of HLH. Level of IL-6 was higher than those of IFN-γ or IL-10 in HLH driven by Systemic auto-inflammatory disorders (SAIDs) or Langerhans Cell Histiocytosis (LCH), while primary HLH and EBV-HLH shared elevated ratio of IL-10 to IL-6. Although more than one distinctive ratios were found in 3 HLH groups, combination of these parameters didn’t offer optimal balance between sensitivity and specificity. Conclusion As a group of easily gained laboratory findings, cytokine levels were reliable in the procedure of roughly classifying HLH cases with the help of patients’ clinical phenotype. However, adequate data is still needed to explore the significance of these indicators in identifying one particular underlying disease accurately.