title: Urinary neopterin quantification by reverse-phase high-performance liquid chromatography with ultraviolet detection.
abstract: Neopterin plays an important role in the malignant disease diagnostics. However, the methods employed in neopterin determination are generally difficult and/or time consuming. The aim of this work was to standardize a practical method to quantify neopterin using high-performance liquid chromatography-ultraviolet (HPLC-UV) and quantify it in patients with systemic lupus erythematosus (SLE). Urine was collected from healthy subjects (n= 49), patients with inactive (n= 15), active (n= 28), and highly active SLE (n= 6). The HPLC was performed using two coupled reverse-phase columns eluted with 150 mM sodium phosphate, pH 4.0, under a flow rate of 0.8 ml/min, with UV detector set at 353 nm and 100-fold diluted urines. The inter- and intra-assay studies presented an imprecision of 12.5% and 12.9% for quality controls of 3.94 and 1.1 micromol/ml, respectively. Recovery from 79.5% to 82% was observed throughout the assay's linear range. Subjects with active (874.2 +/- 165.38 micromol/mol creatinin) and highly active SLE (1753.8 +/- 453.9 micromol/mol creatinin) showed three- and sixfold increased neopterin levels, respectively, compared to subjects with inactive SLE (314.3 +/- 121.3 micromol/mol creatinin) and healthy subjects (294.6 +/- 178.6 micromol/mol creatinin) (P< 0.05). Briefly, the proposed method was precise, specific, and reproducible, not invasive and allows the urinary neopterin quantification only with UV detection.
authors.affiliation: Department of Medicine, Nephrology Division, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu, 740, 04023-900 São Paulo, SP, Brazil.
authors.forename: Marcel Ribeiro
authors.initials: MR
authors.lastname: de Castro
authors.forename: Giovana Seno
authors.initials: GS
authors.lastname: Di Marco
authors.forename: Danielle Yuri
authors.initials: DY
authors.lastname: Arita
authors.forename: Luciana Cristina
authors.initials: LC
authors.lastname: Teixeira
authors.forename: Aparecido Bernardo
authors.initials: AB
authors.lastname: Pereira
authors.forename: Dulce Elena
authors.initials: DE
authors.lastname: Casarini
mesh_terms: D015415:Biomarkers / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis* / Q000652:urine*; D019798:Neopterin / Q000652:urine*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D016482:Urinalysis / Q000379:methods*
chemical_list: D015415:Biomarkers; D019798:Neopterin