Ocular Immunology and Inflammation, 15:303–308, 2007 Copyright  c Informa Healthcare USA, Inc. ISSN: 0927-3948 print; 1744-5078 online DOI: 10.1080/09273940701344374 ORIGINAL ARTICLE Urinary Neopterin Levels in Uveitis: Is It a New Activity Marker? Ali H. Durukan, MD Department of Ophthalmology, Gulhane Military Medical Academy, Ankara, Turkey Volkan Hurmeric, MD Department of Ophthalmology, Gulhane Military Medical Academy, Ankara, Turkey Emin O. Akgul, MD Department of Biochemistry, Gulhane Military Medical Academy, Ankara, Turkey Selim Kilic, MD Department of Epidemiology, Gulhane Military Medical Academy, Ankara, Turkey Mehmet Z. Bayraktar, MD Department of Ophthalmology, Gulhane Military Medical Academy, Ankara, Turkey ABSTRACT Purpose: Neopterin is an immunologic marker for the activation of the cell-mediated immune system and it is found to be elevated in autoimmune diseases. We aimed in this study to investigate the relationship between urinary neopterin levels and disease activity in patients with uveitis. Methods: 31 patients with active uveitis and 13 patients with inactive uveitis were compared with 27 age and sex matched controls. Disease activity was evaluated by clinical examination and fundus florescein angiography findings. Samples were studied with High Performance Liquid Chromatography. Results: Urinary neopterin levels in patients with active uveitis, inactive uveitis and control subjects were 274 ± 98, 179 ± 61 and 166 ± 38 μmol/mol creatinine respectively (p < 001). The difference between active uveitis, inactive uveitis and control groups were statistically significant (p < 001). Conclusions: Urinary neopterin levels are found to be increased in patients with active uveitis. Neopterin can be used as a biochemical activity marker to support the clinical findings in patients with uveitis. KEYWORDS Disease activity; urinary neopterin levels; uveitis INTRODUCTION Neopterin (NP) is a pteridine derivative, which is produced in mono- cytes/macrophages primarily upon stimulation with interferon-γ . 1,2 It is an immunologic marker, especially for the activation of the cell-mediated immune system and is found to be elevated in blood fluids in infections, malignan- cies, allograft rejections, and autoimmune diseases. 2−7 NP is a good indicator of interferon-γ production because it does not undergo extravasation and it is excreted in an unchanged form via the kidneys. 9 NP levels also reflect the amount of hydrogen peroxide produced and ox- idative stress caused by the immune system activities. 8 NP production begins before T cell proliferation and specific antibody production. Therefore, NP may have a clinical value as an early inflammation marker and it has a potential to be used to investigate the present state of cell-mediated immune response and to allow monitoring and prognosis of disease progression. 1−9 Enzyme-linked im- munosorbent assay (ELISA), radioimmunoassay (RIA), and high-performance Received 07 December 2007 Accepted 14 March 2007. Correspondence and reprint request to: Ali H. Durukan, Department of Ophthalmology, Gulhane Military Medical Academy, Ankara, Turkey; e-mail: ahakand@yahoo.com 303