Clinical Implications of Procalcitonin in Kawasaki Disease: A Useful Candidate For Differentiating From Sepsis and Evaluating IVIG Responsiveness

Abstract Objective Kawasaki disease (KD) is a common childhood vasculitis absent of the specific laboratory definitions, besides a significant elevation in several inflammatory mediators, such as procalcitonin (PCT). However, whether PCT can serve as a useful candidate for differentiating KD from sepsis, and even for predicting incomplete KD, intravenous immunoglobulin (IVIG) nonrespondsiveness and coronary artery abnormalities (CAAs) remains unclear.Methods 254 Chinese KD children were enrolled and divided into 6 subgroups, including complete KD, incomplete KD, IVIG-responsive KD, IVIG-nonresponsive KD, KD with CAAs and KD without CAAs. Blood samples were collected from all subjects within 24-h pre- and 48-h post-IVIG infusion, respectively. PCT, C-reactive protein, sedimentation rate and blood cell counts were detected. In addition, both 261 sepsis children and 251 healthy children sex- and age-matched with KD children were enrolled in the same period.Results (1) PCT experienced the highest increase in sepsis patients before antibiotic therapy, followed by acute KD patients and the healthy controls. (2) The proportion of KD patients with a PCT concentration below 0.25 ng/ml was 11 folds higher than that of sepsis patients. (3) PCT had a sensitivity of 91.7% and a specificity of 30.3% at a cut-off value of >0.15 ng/ml to predict IVIG nonresponsiveness, and the proportion of IVIG-nonresponders with a PCT concentration of 0.25-0.50 ng/ml was 2 folds higher than that of IVIG-responders. Conclusions The PCT concentrations below 0.25 ng/ml may be useful for discriminating KD from sepsis, and moreover, the PCT concentrations of 0.25-0.50 ng/ml may be helpful in predicting IVIG nonresponsiveness.