Identification of interferon-beta antibodies in a reference laboratory setting: Findings for 1144 consecutive sera

Clinical studies demonstrate differences in interferon-beta (IFN beta) antibody detection frequencies among multiple sclerosis patients receiving different IFN beta products. We sought to determine if these differences are also found when IFN beta antibodies are measured in a reference laboratory, where factors normally controlled in clinical studies are unknown. Serum IFN beta binding antibodies (BAbs) were quantitated by ELISA; BAbs-positive samples were then tested in a bioassay for neutralizing antibodies (NAbs). Consistent with clinical studies, frequencies of BAbs-positive sera and NAbs-positive sera were lower in the Avonex (IFN beta-1a) treatment group than Rebif (IFN beta-1a) and Betaseron (IFN beta-1b) groups. We further identified a predictive relationship between positive BAbs levels and NAbs activity in patients treated with IFN beta-1a products, but not those treated with IFN beta-1b. (C) 2007 Elsevier B.V. All rights reserved.