Novel HPLC-ICP-MS strategy for the determination of β2-Transferrin, the biomarker of cerebrospinal fluid (CSF) leakage

Abstract

Asialo-Transferrin (S0) or β2-Transferrin is an accepted marker of cerebrospinal fluid (CSF) leakage from the subarachnoid space into the nasal or aural cavity as the result of a head trauma. At this time, the S0 detection method of choice is isoelectric focusing on polyacrylamide gel with direct immunofixation of transferrin (Tf) and silverstaining which are time-consuming techniques (> 5 h). The aim of this study is to present an alternative methodology for determination of Tf sialoforms present in CSF samples, specifically S0, based on the detection of the Fe associated with those forms. A double spiking methodology is developed by saturating the protein with isotopically enriched iron (57Fe) and conducting post-column Isotope Dilution Analysis (IDA) with 54Fe after separation of the different sialoforms by anion exchange chromatography. The results obtained have been validated using a certified serum (ERM®-DA470) and applied with satisfactory results to a pooled CSF sample.