O’Reilly D, Murphy CA, Drew R, et al. - Pediatric sepsis has been challenging to accurately define, thus, this review was conducted to place into context the role of paediatric platelets in the development of fulminant sepsis. Additionally, how platelet transfusions could interfere with the complex links between immune cells in infection was also examined.

• Growing recognition of platelets as important “first responders” to immune threats is obvious.

• The clinical postulation that paediatric platelets and transfused adult platelets have a similar phenotype is likely faulty.

• In pediatric and neonatal sepsis, thrombocytopenia development is common, with trial data indicating worse outcomes in neonates in relation to increased platelet transfusions.

• This is assumed to happen because of a “developmental haemostatic mismatch risk”, where adult platelets compromise the delicate homoeostasis of neonatal bleeding.

• A “developmental immunological mismatch risk” may also be conferred by platelet transfusions with relatively hyperactive platelets and immunologically active extracellular vesicles (EVs).

• Such risk may inadvertently impair outcomes in the presence of an inflammatory stimulus like sepsis.

• EVs are demonstrably different between neonates and adults.