Glycosylation restores survival of chilled blood platelets.

Cooling of blood platelets clusters the von Willebrand factor receptor complex. Macrophage alphaMbeta2 integrins bind to the GPIbalpha subunit of the clustered complex, resulting in rapid clearance of transfused, cooled platelets. This precludes refrigeration of platelets for transfusion, but the current practice of room temperature storage has major drawbacks. We document that alphaMbeta2 is a lectin that recognizes exposed beta-N-acetylglucosamine residues of N-linked glycans on GPIbalpha. Enzymatic galactosylation of chilled platelets blocks alphaMbeta2 recognition, prolonging the circulation of functional cooled platelets. Platelet-associated galactosyltransferase produces efficient galactosylation when uridine diphosphate-galactose is added, affording a potentially simple method for storing platelets in the cold.