Inhibition of haemolysis by the macrophage synthesized antioxidant, 7,8-dihydroneopterin

Neopterin and the reduced form, 7,8-dihydroneopterin (78NP) are pteridines released from macrophages when stimulated with interferon-γ (IFN-γ) in vivo.1,2 The role of 78NP in inflammatory response is unknown, though neopterin has been used clinically as a marker of immune cell activation due to its very fluorescent nature. 78NP is a potent antioxidant in a number of in vitro systems,3–5 leading to the suggestion that it has a role in protecting macrophages from free radical damage during inflammation.3