Recently, mean platelet volume-to-lymphocyte ratio has emerged as a novel parameter of inflammation. No study has investigated the role of mean platelet volume-to-lymphocyte ratio in children with Kawasaki disease. We aimed to evaluate the relationship between mean platelet volume-to-lymphocyte ratio and coronary artery abnormalities in Kawasaki disease.

Between January 2008 and January 2017, a total of 58 children with Kawasaki disease and 42 healthy subjects matched for sex and age were enrolled. Before the treatment, transthoracic echocardiography for all children was performed. Clinical and laboratory results including mean platelet volume, platelet distribution width, red blood cell distribution width, and counts of platelets, neutrophils, lymphocytes, and white blood cells, erythrocyte sedimentation rate, and C-reactive protein levels were measured. Mean platelet volume-to-lymphocyte ratio was calculated as mean platelet volume divided by lymphocyte count.

Compared with healthy controls, mean platelet volume-to-lymphocyte ratio was significantly lower in the children with Kawasaki disease (p<0.01). A total of 14 patients (24.1%) had incomplete Kawasaki disease and 15 (25.8%) children with Kawasaki disease had coronary involvement. Mean platelet volume-to-lymphocyte ratio was significantly lower in patients with coronary artery abnormalities (p<0.01). According to receiver operating characteristic curve analysis performed for the prediction of coronary artery abnormalities, the best cut-off point for mean platelet volume-to-lymphocyte ratio was 2.5 (area under curve=0.593, sensitivity 53.3%, specificity 51.1%).

It was first shown that the children with Kawasaki disease have lower mean platelet volume-to-lymphocyte ratio compared with control subjects. Mean platelet volume-to-lymphocyte ratio may be helpful in predicting coronary artery lesions in patients with Kawasaki disease.

The aim of the present study was to investigate the relationships between red blood cell distribution width, platelet distribution width, and mean platelet volume and the presence and severity of valvular involvement in patients with rheumatic heart disease.

Between April, 2012 and December, 2015, 151 patients who were admitted to the Pediatric Cardiology Unit with diagnosis of rheumatic heart disease and 148 healthy children were included to our study. Transthoracic echocardiography for all children was performed, and the values of red blood cell distribution width, platelet distribution width, and mean platelet volume, besides other blood count parameters, erythrocyte sedimentation rate, and C-reactive protein levels were recorded.

Red blood cell distribution width, platelet distribution width, mean platelet volume, and C-reactive protein levels were significantly higher in patients with rheumatic heart disease when compared with healthy controls (p<0.01). Red blood cell distribution width was positively correlated with both C-reactive protein (r=0.271, p=0.035) and erythrocyte sedimentation rate (r=0.308, p=0.006). When single valve involvement was compared with both aortic valve and mitral valve involvement in the study group, red blood cell distribution width and platelet distribution width were higher in patients with double valve involvement; however, this was not statistically significant (p>0.05).

This is the first study in children with rheumatic heart disease that demonstrated significantly increased red blood cell distribution width, platelet distribution width, and mean platelet volume levels, as well as evaluated all three parameters together. Furthermore, red blood cell distribution width values in the chronical period of acute rheumatic fever, due to the positive correlation with the other chronic inflammatory markers, may help make the diagnosis in children.