• Chediak–Higashi syndrome;
  • cardiac failure;
  • diadenosine polyphosphates;
  • fever

A 14-week-old boy with undiagnosed Chediak–Higashi syndrome developed fever with a high temperature and acute cardiac failure after having received a scheduled vaccination. We hypothesize that decreased concentrations and receptor binding of serum and tissue diadenosine polyphosphates, such as AP4A, AP5A, or AP6A, which are stored in various tissues and serve as extra-cellular signaling molecules or are secreted by cells in response to physiologically stressful stimuli, lead to the observed severe tachyarrhythmia. Diadenosine polyphosphates normally have a negative chronotropic and inotropic effect. This is the first report of severe cardiac failure in a child with Chediak–Higashi syndrome and we suggest that cardiac arrhythmias should be considered in such children in the event of high fever. Our hypothesis requires further investigation in other patients.