Downregulation of Th17 cells and the related cytokines with treatment in Kawasaki disease

Highlights

• Higher proportion of Th17 cells is associated with KD.

• Higher levels of IL-17, IL-22 and IL-23 are associated with KD.

• Treatment decreased the proportion of Th17 cells.

• Treatment downregulated the levels of the mentioned cytokines.

• The results from the sera confirmed the cultured PBMCs supernatants results.

Abstract

Given the inflammatory nature of Kawasaki disease (KD) and the pro-inflammatory properties of Th17, this study aimed to determine the frequency of Th17 cells and the levels of corresponding cytokines in acute phase of KD and to evaluate their alterations one and eight weeks after treatment. Th17 and the related cytokine levels were measured in 21 KD patients and 42 positive and negative controls, using flow cytometry and ELISA, respectively. Th17, IL-17, IL-22 and IL-23 were significantly higher (P < 0.05) in patients compared with negative controls, but no significant differences (P > 0.05) with the positive controls. Furthermore, Th17, IL-17, IL-22 and IL-23 were significantly higher in patients before treatment than those one and eight weeks after. Considering the downregulation of Th17 and its related cytokines with aspirin and intravenous immunoglobulin therapy implies the probable role of Th17 in KD pathogenesis.

Introduction

Kawasaki disease (KD), is an acute febrile systemic vasculitis which mostly appears in infants and early childhood [1]. The disease is characterized by different clinical manifestations consisting of fever persisting for 5 days, polymorphic rash, conjunctivitis, mucosal erythema with strawberry tongue, induration of the hands and feet, and acute non-purulent unilateral cervical lymphadenopathy [2]. Given the involvement of the coronary arteries, KD is known to be the leading cause of acquired heart disease in children in developed countries [3]. Ischemic heart disease, the consequence of coronary artery aneurysms, is the most common cause of death in the children [4]. It has been revealed that both arms of the immune system (innate and adaptive) are involved in the pathogenesis of vasculitis, which is the consequence of the migration and activation of neutrophils, macrophages and lymphocytes in the arterial wall approximately ten days after the onset of the disease. This process is the cause of inflammation of all layers of the arteries [5], [6]. Several lines of evidence pointed that neutrophils along with macrophages and monocytes can cause damage to the endothelial cells by production of reactive oxygen species, local matrix metaloproteases and elastase [7], [8], [9]. Recruitment of neutrophils and monocytes and their secreted products in the inflammatory sites are enhanced by colony stimulating factors (CSF) such as granulocyte and monocyte-CSF (GM-CSF and G-CSF) as well as CXCL chemokines which consist of CXCL8 (IL-8), CXCL1, and CXCL6 (GCP2). The production of these CSFs and chemokines is shown to be stimulated by IL-17 [10], [11], a highly pro-inflammatory cytokine produced by a distinct lineage of T helper (h) cells, i.e., Th17 [12]. Th17 is derived from circulating naïve T cells in which IL-23 and IL-1β seem to be influential in this process in humans [13], [14]. The cell produces a subset of cytokines such as IL-6, IL-21 and IL-22 and induces CCR6 and CCR4 in the skin and mucosa leading to the infiltration of neutrophils and monocytes within the tissues [15]. Th17 is recently understood as the effective defense against certain extracellular pathogens invading mucosal surfaces [16], [17], and its association with different autoimmune inflammatory diseases such as rheumatoid arthritis and multiple sclerosis, crohn's disease and psoriasis has been clarified as well [18], [19], [20]. These findings raise the possibility that increased frequency of Th17 and high concentration of the corresponding cytokines may be involved in the pathogenesis of the KD and its clinical manifestations.

The present study seeks to investigate the frequency of Th17 and the levels of IL-17, IL-22 and IL-23 at the onset of KD diagnosis, compared with those in healthy individuals and also in the patients with an inflammatory disease such as febrile pneumonia and track their changes following the treatment.