Dynamics of interferon-β modulated mRNA biomarkers in multiple sclerosis patients with anti-interferon-β neutralizing antibodies

The objective of this study was to evaluate multiple interferon (IFN) specific mRNA biomarkers in multiple sclerosis (MS) patients with anti-IFN-β neutralizing antibodies (NAB) using a pharmacodynamic study design.Thirty patients were enrolled. Blood samples were drawn at pre-treatment, 4-, 8-h time points following the intramuscular dose of IFN-β-1a. Total RNA was obtained from peripheral blood cells, processed to cDNA and analyzed using quantitative real-time polymerase chain reaction. Pre-treatment serum samples were analyzed for anti-IFN-β binding and neutralizing antibodies: 22 patients were NAB negative; equal numbers of the eight remaining patients were either NAB positive or had borderline NAB status. The results showed that early assessment (at 4 h after IFN-β injection) of mRNAs for Stat-1, MxA, MxB and TRAIL was more sensitive than the later measurements. Furthermore, the NAB positive patients had strongly attenuated gene expression responses on all the mRNAs. Patients with borderline NAB had average responses that appear to be lower than NAB negative patients on several genes, notably Stat-1, TRAIL and β2 microglobulin.