Value of degenerative change in neutrophils as a diagnostic test for Kawasaki syndrome

Kawasaki disease

Kawasaki disease is a systemic vasculitis and the leading cause of acquired heart disease in North American and Japanese children. The epidemiology, cause, and clinical characteristics of this disease are reviewed. The diagnostic challenge of Kawasaki disease and its implications for coronary artery outcomes are discussed, as are the recommended treatment, ongoing treatment controversies, concerns associated with treatment resistance, and the importance of ongoing follow up.

Intravenous immunoglobulin therapy induces neutrophil apoptosis in Kawasaki disease

To investigate the effect of high-dose intravenous immunoglobulin (IVIg) on neutrophil apoptosis in Kawasaki disease (KD), we studied the in vitro spontaneous and IVIg-induced apoptosis of neutrophils by analyzing a proportion of annexin V-positive cells and cells with fragmented DNA. The mean number of peripheral neutrophils in the post-IVIg phase decreased significantly (P < 0.01) compared with that in the pre-IVIg phase. The mean proportion of spontaneous apoptotic neutrophils in the post-IVIg phase was significantly higher (P < 0.01) than that in the pre-IVIg phase, and there was a significantly positive correlation (P < 0.01) with the reduction ratio of the circulating neutrophil counts from the pre-IVIg through the post-IVIg phases. IVIg induced a dose-dependent increase in the proportion of apoptotic neutrophils in the pre-IVIg phase. As a result, the present study demonstrated a novel action in which high-dose IVIg therapy decreased the number of circulating neutrophils by accelerating their apoptosis in KD.

Delayed apoptosis of circulating neutrophils in Kawasaki disease

Circulating polymorphonuclear neutrophils (PMNs) are known to increase in number and are functionally activated in the acute phase of Kawasaki disease (KD). In the present study, we investigated whether the apoptosis of PMNs is deregulated in KD. When the isolated PMNs were cultured in vitro, the proportions of spontaneous apoptotic PMNs (annexin V+ cells and cells with fragmented DNA) were found to be significantly lower (P < 0.01) in the patients with KD (n = 25) than in the patients with a bacterial infection (n = 20) or a viral infection (n = 20), or in healthy children (n = 20). The proportion of circulating Fas-positive PMNs was also significantly lower (P < 0.01) in the acute KD patients than in the other groups. In the acute phase of KD, the proportion of spontaneous apoptotic PMNs showed a significant positive correlation (P < 0.01) with the proportions of circulating Fas-positive PMNs. Furthermore, the agonistic anti-Fas MoAb (CH-11) induced a significant increase in the proportion of apoptotic PMNs in the patients with a viral infection and healthy children, but not in either the patients with KD or the patients with a bacterial infection. In the intracellular expression of anti- and pro-apoptotic proteins, the A1/Bax ratio was significantly higher in acute KD than in the other groups. These findings indicate that PMN apoptosis is inhibited during the acute phase of KD and also suggest that both the resistance against the Fas-mediated death signal and the down-regulation of the mitochondrial apoptotic signalling pathway due to an altered balance of Bcl-2 protein expression are responsible for the delayed PMN apoptosis.

Neutrophils and mononuclear cells express vascular endothelial growth factor in acute Kawasaki disease: its possible role in progression of coronary artery lesions

Kawasaki disease (KD) is a syndrome of systemic vasculitis of unknown etiology that is complicated by coronary artery lesions (CAL), leading occasionally to cardiac ischemic sequelae. To examine whether vascular endothelial growth factor (VEGF) is responsible for CAL in KD, we determined serum VEGF levels by ELISA and peripheral blood mononuclear cell (PBMC) and neutrophil VEGF expression by immunoblot analysis. Significantly increased levels of VEGF were demonstrated in acute KD as well as in other vasculitis syndromes (p < 0.0001). In the 10 KD patients with CAL, serum VEGF levels were maximal approximately 2 wk post-onset when CAL generally develops and were significantly higher than in 20 patients without CAL (mean, 474 and 241 pg/mL, respectively; p = 0.00015). During the same period, immunoblot analysis revealed maximal VEGF expression in PBMC, corresponding to serum VEGF levels in most patients and being particularly marked in patients with CAL (p < 0.01). Neutrophils expressed VEGF only in the early stage of acute KD and declined rapidly in the majority of KD patients regardless of the presence of CAL, showing a strikingly different expression pattern than that for PBMC. Predominant VEGF expression by PBMC was also demonstrated in patients with other vasculitis syndromes and only faintly in normal controls. The results suggest that VEGF is generated dynamically in KD, presumably reflecting its disease activity. Neutrophil-derived VEGF may play a role in regulating early vascular responses, whereas PBMC-derived VEGF may contribute to later vascular injury and remodeling.

Expression of IL-8 in Kawasaki disease

We investigated, by Northern blotting, ELISA, and a chemotaxis assay, the expression of IL-8 mRNA, the production of IL-8 protein, and the biological activity of mononuclear cells (MNC), polymorphonuclear neutrophils (PMN) and plasma, respectively, from patients with Kawasaki disease (KD) who received intravenous immunoglobulin (IVIG). IL-8 mRNA expression by MNC and PMN, the level of IL-8 protein, and the neutrophil chemoattractant activity within plasma were all increased in the acute phase of KD, and were significantly elevated following IVIG therapy. The level of chemotactic activity of neutrophils, but not that of monocytes, in response to F-met-leu-phe was decreased in patients with KD after IVIG. The increased expression of IL-8 in PMN and MNC, the increased plasma level of IL-8 and the decreased level of neutrophil chemotactic activity of the patients who received IVIG therapy might inhibit the accumulation of neutrophils at the sites of inflammation, and may thus reduce the risk of aneurysm formation.

Early reactive neutrophil changes in an infant with Kawasaki syndrome

An infant with Kawasaki syndrome presenting with fever, rash, and a high percentage of neutrophils with toxic granulation is reported. The peripheral blood smears of the patient showed a high proportion of neutrophils with marked vacuoles and toxic granulations. The reactive changes in neutrophils could be helpful in the early detection of the disease, especially in infants younger than 6 months of age who are at high risk for development of coronary artery disease.

Leukocyte counts in patients with Kawasaki disease: from the results of nationwide surveys of Kawasaki disease in Japan

In the latest survey of Kawasaki disease in Japan, questionnaires on maximal leukocyte counts of the patients were included to clarify whether leukocyte counts could be of value for the diagnosis and prediction of outcome. A questionnaire form and diagnostic guidelines for Kawasaki disease were sent to all pediatric departments of hospitals with > or = 100 beds throughout Japan, and information including maximal leukocyte counts was obtained on patients with Kawasaki disease diagnosed during the 2-y period from January 1993 to December 1994. Of the 11,458 patients diagnosed during the 2-y period, maximal leukocyte counts were reported in 11,062 patients (96.5%). The mean value and the distribution of maximal leukocyte counts were lower in the age group under 1 y. The mean values and the distribution of leukocyte counts were lowest in suspected cases among three diagnostic categories: typical cases of Kawasaki disease, atypical cases, and suspected cases. The mean values of maximal leukocyte counts of the patients with cardiac sequelae were significantly higher than those without cardiac sequelae in each age group. The proportion of patients with cardiac sequelae increased with leukocyte counts in each age group. The Receiver/Response Operating Characteristic (ROC) curve for maximal leukocyte counts in Kawasaki disease revealed that the accuracy of maximal leukocyte counts for prediction of cardiac sequelae was highest in the age group < 6 months, and the most accurate cut-off point was 16 x 10(9)/l. The strongest association between higher leukocyte counts (> or = 16 x 10(9)/l) and cardiac sequelae was observed in the age group < 6 M. A large-scale analysis of leukocyte counts in patients with Kawasaki disease revealed age-dependent relationship between maximal leukocyte counts, diagnostic categories and outcome. Maximal leukocyte counts may be helpful for the prediction of outcome with the consideration of age.