HIF1A and infection: Moreover, the macrophage response to bacterial lipopolysaccharide (LPS) is enhanced under hypoxia, through HIF-1-mediated, increased toll-like receptor (TLR) gene expression, resulting in increased expression of cyclooxygenase-2, interleukin-6 and Regulated on Activation, Normal T Cell Expressed and Secreted (RANTES) (52, 53), suggesting that hypoxic conditions may contribute to the aggravated inflammatory responses during infection.