Alteration of CD4CD25Foxp3 T cell level in Kawasaki disease

CD8+ T Cells Contribute to the Development of Coronary Arteritis in the Lactobacillus casei Cell Wall Extract-Induced Murine Model of Kawasaki Disease

OBJECTIVE

Kawasaki disease (KD) is the leading cause of acquired heart disease among children in developed countries. Coronary lesions in KD in humans are characterized by an increased presence of infiltrating CD3+ T cells; however, the specific contributions of the different T cell subpopulations in coronary arteritis development remain unknown. Therefore, we sought to investigate the function of CD4+ and CD8+ T cells, Treg cells, and natural killer (NK) T cells in the pathogenesis of KD.

METHODS

We addressed the function of T cell subsets in KD development by using a well-established murine model of Lactobacillus casei cell wall extract (LCWE)-induced KD vasculitis. We determined which T cell subsets were required for development of KD vasculitis by using several knockout murine strains and depleting monoclonal antibodies.

RESULTS

LCWE-injected mice developed coronary lesions characterized by the presence of inflammatory cell infiltrates. Frequently, this chronic inflammation resulted in complete occlusion of the coronary arteries due to luminal myofibroblast proliferation (LMP) as well as the development of coronary arteritis and aortitis. We found that CD8+ T cells, but not CD4+ T cells, NK T cells, or Treg cells, were required for development of KD vasculitis.

CONCLUSION

The LCWE-induced murine model of KD vasculitis mimics many histologic features of the disease in humans, such as the presence of CD8+ T cells and LMP in coronary artery lesions as well as epicardial coronary arteritis. Moreover, CD8+ T cells functionally contribute to the development of KD vasculitis in this murine model. Therapeutic strategies targeting infiltrating CD8+ T cells might be useful in the management of KD in humans.

Th17- and Treg-related cytokine and mRNA expression are associated with acute and resolving Kawasaki disease

BACKGROUND

Kawasaki disease is a vasculitis most commonly afflicting children <5 years of age. Many autoimmune diseases are associated with up-regulation of T helper (Th) 17 cells, and down-regulation Treg cells. Few studies have examined the Th17/Treg expression in Kawasaki disease.

METHODS

Blood samples were obtained from 186 children with Kawasaki disease at 24 h before IVIG therapy, followed by 3 days and 21 days after IVIG therapy. Thirty children with an acute febrile infectious disease and 30 healthy children were obtained as control. Plasma levels of Th17- and Treg-related cytokines including IL-6, IL-17A, IL-10, TGF-β, and mRNA expression levels of RORγt and Foxp3 were tested.

RESULTS

Patients with Kawasaki disease had higher levels of plasma IL-17A (25.35 ± 3.21 vs 7.78 ± 1.78 pg/ml, P < 0.001) and IL-6 (152.29 ± 21.94 vs 38.63 ± 12.40 pg/ml, P < 0.001) when compared to the febrile control group. IVIG resulted in a reduction in IL-6 and IL-17A at both 3 and 21 days after IVIG therapy. FoxP3 levels increased significantly 3 days after IVIG therapy (2.28 ± 0.34 vs 0.88 ± 0.14, P < 0.001). IVIG resistance was associated with higher levels of IL-10 and IL-17A.

CONCLUSION

Kawasaki disease was associated with higher IL-17A and IL-6, a cytokine profile similar to other autoimmune diseases. IVIG therapy resulted in increased expression of Treg-related FoxP3. IVIG resistance was associated with higher levels of IL-10 and IL-17A. Our findings provide further evidence that Kawasaki disease is an autoimmune-like disease.

Lack of CD4⁺CD25⁺FOXP3⁺ regulatory T cells is associated with resistance to intravenous immunoglobulin therapy in patients with Kawasaki disease

The aim of this study was to investigate changes in CD4(+)CD25(+)FOXP3(+) regulatory T cells (Tregs) throughout the clinical course of Kawasaki disease (KD) and correlations with response to intravenous immunoglobulin (IVIg) therapy. Participants comprised 18 patients who fulfilled the diagnostic criteria for KD and 20 healthy subjects. Expressions of CD25 and FOXP3 among all CD4(+) T cells in peripheral blood mononuclear cells were analyzed by flow cytometry before and 7 and 30 days after IVIg therapy. Before treatment, percentages of CD4(+)CD25(+)FOXP3(+) Tregs among total CD4(+) Tregs were significantly lower among KD patients (4.19 %; range, 0.16-8.11 %) than among healthy subjects (7.32 %; 4.18-13.42 %; P = 0.0001). Both percentages and absolute numbers of CD4(+)CD25(+)FOXP3(+) Tregs on day  7 after IVIg therapy were significantly increased compared with values before treatment (8.02 % (range, 0.51-12.6 %) vs. 4.19 % (range, 0.16-8.11 %), P = 0.0005; 93.25/ μL (range, 6.67-258.05) vs. 41.85/ μL (range, 0.44-160.62), P < 0.0001, respectively). Moreover, percentages and absolute numbers of CD4(+)CD25(+)FOXP3(+) Tregs before treatment were significantly lower in the IVIg-resistant group than in the IVIg-sensitive group (0.18 % (range, 0.16-3.34 %) vs. 4.52 % (range, 2.8-8.11 %), P = 0.0022; 0.68/μL (range, 0.44-53.81) vs. 51.66/μL (range, 2.88-160.62), P = 0.0098, respectively). The frequency of CD4(+)CD25(+)FOXP3(+) Tregs in four of the five IVIg-resistant patients at diagnosis was more than 3 standard deviations below that in healthy subjects. Two of these four patients displayed coronary abnormalities, and one of these two patients developed coronary aneurysm.

CONCLUSION

Lack of CD4(+)CD25(+)FOXP3(+) Tregs before treatment may predict resistance to IVIg therapy in patients with KD.

Important role of CCR2 in a murine model of coronary vasculitis

Background

Chemokines and their receptors play a role in the innate immune response as well as in the disruption of the balance between pro-inflammatory Th17 cells and regulatory T cells (Treg), underlying the pathogenesis of coronary vasculitis in Kawasaki disease (KD).

Results

Here we show that genetic inactivation of chemokine receptor (CCR)-2 is protective against the induction of aortic and coronary vasculitis following injection of Candida albicans water-soluble cell wall extracts (CAWS). Mechanistically, both T and B cells were required for the induction of vasculitis, a role that was directly modulated by CCR2. CAWS administration promoted mobilization of CCR2-dependent inflammatory monocytes (iMo) from the bone marrow (BM) to the periphery as well as production of IL-6. IL-6 was likely to contribute to the depletion of Treg and expansion of Th17 cells in CAWS-injected Ccr2^+/+ mice, processes that were ameliorated following the genetic inactivation of CCR2.

Conclusion

Collectively, our findings provide novel insights into the role of CCR2 in the pathogenesis of vasculitis as seen in KD and highlight novel therapeutic targets, specifically for individuals resistant to first-line treatments.