Interferon gamma levels are reduced by adenosine 5'-triphosphate in lipopolysaccharide-stimulated whole human blood

Extracellular release of ATP is an important modulator of immune response. ATP plasma concentration is increased in sepsis [1]. IFNγ plays a critical role in host defense by promoting Th1 phenotype and bacterial clearance. Low IFNγ levels are associated with the Th2 phenotype consistent with critical illness anergy [2]. It has been reported that 100 and 300 mM ATP increased LPS/PHA-stimulated IL-10 secretion in human blood [3]. Higher IL-10/IFNγ ratio shifts the immune phenotype from Th1 to Th2 response. We studied the effect of ATP on LPS-stimulated IL-10 and IFNγ secretion in a standardized ex-vivo whole human blood culture.