Comparison of Serum Interleukin-18 Levels, Biochemical Profiles and the Duration of Fever in the Acute and Subacute Phase of Kawasaki Disease

ABSTRACT

PURPOSE: Interleukin 18 (IL-18) is now recognized as an important regulator of innate and acquired immune response. IL-18 is a proinflammatory cytokine which induces IFN-gamma, TNF-alpha, Granulocyte-macrophage Colony-stimulating factor (GM-CSF), IL-1, IL-4 and IL-10, to activate killing by lymphocytes, and to up-regulate the expression of certain chemokine receptors. The authors hypothesized that elevated concentration of IL-18 was related to the pathophysiology of KS. The aims of the present study was to evaluate serial changes of serum IL-18 level in acute and subacute phase of KD, and Comparison of serum IL-18 levels, biochemical profiles and the duration of fever. METHODS: We determined simultaneously the serum concentrations of IL-18 and C-reactive protein (CRP) as well as the white blood cell (WBC) count in 23 patients with acute and subacute phase of KD, 23 with respiratory tract infection (febrile controls) and 10 healthy children (afebrile controls). RESULTS: Acute-phase KD patients showed a significantly higher mean IL-18 value (492.80+/-143.70 pg/mL) than that of subaute-phase KD patients(230.67+/-144.13 pg/mL) and afebrile control (223.97+/-164.12 pg/mL)(p<0.05). Subacute-phase KD patients showed a significantly lower level of IL-18 compared to febrile control(519.77+/-242.05 pg/mL)(P<0.05). The IL-18 values in the acute-phase patients showed a positive correlation with CRP (r=0.413, P=0.030), but there were no other correlations between serum IL-18 value and other profiles. CONCLUSION: The results showed increased IL-18 values in the acute phase and normal values in subacute phase of KD. but IL-18 values were not directly correlated with WBC count, CRP and the duration of fever except between IL-18 value and CRP in the acute phaseof KD. The results suggest that IL-18 pathways were activated in the acute phase of KD, and IL-18 production may not be associated with the severity of inflammation in KD.