Expression of Eosinophilic Subtype Markers in Patients with Kawasaki Disease.

PURPOSE

Eosinophils may rise to a higher level in the acute phase of Kawasaki disease (KD) both before and after intravenous immunoglobulin (IVIG) therapy. A substantial body of research was carried out on the association between KD and allergic diseases. Eosinophils play an important role in type 2 inflammation. Recent studies have shown that there are two distinct subtypes of eosinophils. In addition to their role in inflammation, lung-resident eosinophils (rEOS) also regulate homeostasis. Inflammatory eosinophils (iEOS) reflect type 2 inflammation in tissues. iEOS were considered the primary eosinophils in non-severe allergic asthma, while rEOS were thought to be the primary eosinophils in severe non-allergic eosinophilic asthma. This case-control study aimed to investigate the marker expression of eosinophilic subtypes in KD patients.

MATERIALS AND METHODS

The marker expressions of eosinophilic subtypes in the leukocytes of patients with KD were evaluated by the recently established KDmarkers online tool, a web server including gene expression data. Finally, the results were validated with a quantitative reverse transcriptase polymerase chain reaction (RT-PCR). We analyzed the mRNA expression levels of and in leukocytes from KD patients and febrile children.

RESULTS

Included in our screening tools were transcriptome arrays, which provided clues showing the importance of rEOS, whose role was identified by three genes (lower , higher and than controls). In contrast, the iEOS representative gene was not elevated in KD. It was found that the gene , a marker of inflammatory eosinophilic leukocytes, was more highly expressed in the leukocytes of KD patients ( = 43) than febrile controls ( = 32), especially those without coronary artery lesions (CAL) ( = 26). Before treatment, expression was higher in leukocytes of CAL patients (CAL, 1.33 ± 0.18, = 39; non-CAL, 0.87 ± 0.12, = 55; = 0.012). was significantly higher after half a year compared to febrile controls.

CONCLUSIONS

To our knowledge, this is the first study to demonstrate that KD patients have increased than febrile controls after 6 months of treatment. We present evidence here that dynamically different eosinophilic involvement exists between KD patients with and without CAL. The role of eosinophilic subtypes in KD patients warrants further investigation.