RESEARCH ARTICLE Indoleamine 2,3 Dioxygenase (IDO) Expression and Activity in Relapsing- Remitting Multiple Sclerosis

Background Interferon gamma (IFN-γ) production induces the transcription of indoleamine 2,3 dioxygenase (IDO) resulting in the reduction of T-cell activation and proliferation through the depletion of tryptophan and the elicitation of Treg lymphocytes. IDOwas shown to be involved in the patho-genesis of autoimmune diseases; we investigated whether changes in IDO gene expression and activity could be indicative of onset of relapse in multiple sclerosis (MS) patients. Methods IDO and interferon-γ (IFN-γ) gene expression, serum IDO activity (Kynurenine/Tryptophan ratio) and serum neopterin concentration – a protein released by macrophages upon IFN-γ stimulation – were measured in 51 individuals: 36 relapsing remitting (RR)-MS patients (21 in acute phase-AMS, 15 in stable phase-SMS) and 15 healthy controls (HC). PBMCs sam-ples in AMS patients were collected before (BT-AMS) and during glucocorticoids-based therapy (DT-AMS). Result