Elevated Serum Free Carnitine Levels in Children with Kawasaki Disease and Their Relation to Unresponsiveness to Intravenous Immunoglobulin: retprospective study

Abstract

Background Carnitine plays an essential role in transfer of long-chain fatty acids to mitochondria for subsequent β-oxidation. No studies to date have characterized carnitine in children with KD. The objective of this study is to investigate the characteristics of serum free carnitine (FC) in hospitalized pediatric patients with Kawasaki disease (KD). Methods In total, 45 patients with KD measured the levels of serum FC from October 2018 to December 2019 were analyzed retrospectively. We analyzed the clinical and laboratory parameters just before the Intravenous immunoglobulin (IVIG) including serum levels of serum FC with respect to the IVIG response. Results The median age was 33 months. IVIG was effective in 33 children (responders) and was ineffective in 12 (non-responders). The serum FC levels were higher in non-responders than in responders [(35.3 µmol/L (range, 26.8-118.4 µmol/L) vs. 31.4 µmol/L (range, 20.9–81.2 µmol/L), p value = 0.0496]. The FC levels before intravenous immunoglobulin (IVIG) in four-fifths of responders were below the normal range.The levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin, and FC were higher in non-responders than in responders. There was a correlation between FC and AST (R2 = 0.364, P = 0.0015) and between FC and ALT (R2 = 0.423, P < 0.001) levels. Conclusion FC levels were upregulated in patients with KD who were refractory to IVIG. Additionally, FC levels in children with KD correlated with AST and ALT levels. The pathogenesis resulting in the elevation of FC levels remains elusive. Further studies are necessary to understand more precisely carnitine properties in patients with KD.