Characterization of circulating immune cells in acute Kawasaki disease suggests exposure to different antigens.

Kawasaki disease (KD) is an acute pediatric vasculitis of unknown etiology that can cause coronary artery aneurysms, and is the leading cause of acquired heart disease in children. We studied aspects of the innate and adaptive immune response in 17 acute KD children prior to treatment with intravenous immunoglobulin. Distinct patterns within the innate immune response correlated with specific clinical features. Proinflammatory myeloid dendritic cells (mDC) were abundant in four of 17 (23·5%) subjects who were older and manifested severe inflammation with clinical myocarditis and elevated hepatobiliary enzyme levels. Of the nine subjects with low levels of anti-inflammatory, tolerogenic mDC, six had enlarged cervical lymph nodes at diagnosis. In contrast, the adaptive immune repertoire varied greatly with no discernible patterns or associations with clinical features. Two subjects with aneurysms had numerous circulating CD8+ T cells. Ten subjects showed low CD4+ T cell numbers and seven subjects had CD4+ T cells in the normal range. CD4+ T cells expressed interleukin-7 receptor (IL-7R), suggesting repeated antigenic stimulation. Thymic-derived regulatory T cells (nTreg ) and peripherally induced regulatory T cells (iTreg ) were also enumerated, with the majority having the nTreg phenotype. Natural killer (NK) and NK T cell numbers were similar across all subjects. Taken together, the results of the immune monitoring suggest that KD may have multiple triggers that stimulate different arms of the innate and adaptive compartment in KD patients. Thus, it is possible that diverse antigens may participate in the pathogenesis of KD.

CD45RO+ memory T-cells produce IL-17 in patients with atherosclerosis.

Several CD4+ T helper (Th) cell subsets are shown to play a role in atherosclerotic lesion formation and progression. We investigated the frequencies of IL-17 and IFN-γ producing CD4+ T-cell subsets in the peripheral blood mononuclear cells (PBMCs) of 10 patients with atherosclerosis and 6 individuals with normal/insignificant coronary artery disease. Th1 and Th17 memory and effector T-cells were enumerated by flowcytometry and correlated with the clinical data and lipid profiles of the subjects. We found the ex-vivo (P=0.0001) and in-vitro production of IL-17 (P=0.001) but not IFN-γ by CD4+ memory T-cells of patients. CD45RO+ memory cells were the major producers of IL-17 and the CD4+CD45RO+PD-1- T-cells of the patients produced higher levels of IFN-γ than controls (P=0.02). Positive correlations between the frequency of CD4+CD45RO+IL-17+IFN-γ- T-cells and serum LDL-C (P=0.007), triglyceride (P=0.02), and systolic (P=0.001) and diastolic (P=0.009) blood pressures (BP) were found. The frequency of CD4+CD45RO+IL-17-IFN-γ- T-cells, which was higher in controls than patients, showed negative correlations with the serum LDL-C (P=0.01) and triglyceride (P=0.02) levels and systolic (P=0.003) and diastolic (P=0.01) BPs. The ex-vivo Th17 deviation of memory T-cells in atherosclerosis and high PD-1 expression are associated with the correlates of atherogenesis such as LDL, TG, and BP.