Neopterin production and tryptophan degradation during 24-months therapy with interferon beta-1a in multiple sclerosis patients

Background Increased synthesis of neopterin and degradation of tryptophan to kynurenine, measured as kynurenine/tryptophan ratio (kyn/trp ratio), are considered in vitro markers of interferon beta-1a (IFNβ-1a) activity. The aim of the study was to investigate the dynamic profile of neopterin and kyn/trp ratio in patients with relapsing remitting multiple sclerosis (RRMS) treated with two different doses of IFNβ-1a over a period of 24 months.