KIM-1 levels spike after PRBC transfusion in infants

Transfusion of packed red blood cells (PRBCs) in infants may trigger a slight and transient inflammatory status, signalled by an increase in levels of the inflammatory marker kidney injury molecule-1 (KIM-1), a recent study has found.

The study included 34 infants whose urinary KIM-1 levels were measured before and 6, 12, and 24 hours after PRBC transfusion. Blood transfusions correlated with significant changes in the natural log of KIM-1 concentrations over time.

Before PRBC, median KIM-1 concentration was 2,270 pg/mg, which peaked 6–12 hours after transfusion, reaching a high of 3,300 pg/mg (p<0.01 relative to baseline). Twenty-four hours after transfusion, urinary KIM-1 dropped back down to 2,240 pg/mg, which was not significantly different from pre-transfusion levels (p=0.63).

Multivariable analysis adjusted for pretransfusion KIM-1 concentrations and the volume of blood received confirmed that PRBC transfusions significantly correlated with significant changes in urinary KIM-1 concentrations over the three post-transfusion time points (p<0.01).

The present findings reveal “a timeline of when KIM-1 levels peak and how long it takes for them to return to the pretransfusion status. This timeline may help in further evaluating the pathophysiology of transfusion-associated organ injury,” the researchers said.

“Future studies may elect to study if blood transfusions negatively influence renal artery perfusion,” they added. “KIM-1 as an inflammatory marker may be considered in future studies evaluating the responses of the body to different transfusion volumes.”