title: The importance of measuring IFNbeta bioactivity: monitoring in MS patients and the effect of anti-IFNbeta antibodies.
abstract: Many multiple sclerosis (MS) patients treated with IFNbeta develop anti-IFNbeta antibodies, which can interfere with the bioactivity of the injected cytokine, i.e., antibody-mediated decreased bioactivity (ADB). The precise levels of anti-IFNbeta antibodies inducing decreased bioactivity is unknown. We repeatedly used a bioactivity measure, gene expression of MxA or GEM, and correlated bioactivity with measures of binding and neutralizing antibodies. The binding antibody assay was a capture ELISA, and the neutralizing antibody (NAb) assay was a cytopathic effect (CPE) assay. 27% (17/64) of patients repeatedly sampled developed critical ADB. Bioactivity as determined by GEM correlated negatively with NAb titer, and bioactivity that had been lost with the development of NAbs returned if NAb levels diminished. These data reveal that the GEM assay is a useful adjunct in the management of MS patients treated with IFNbeta, and that lost bioactivity returns when anti-IFNbeta antibody levels diminish.
authors: Department of Neurology and Neurosciences, UMDNJ-New Jersey Medical School, 185 S. Orange Ave., Newark, NJ 07103, USA. pachner@umdnj.edu
authors: Andrew R
authors: AR
authors: Pachner
authors: Donna
authors: D
authors: Dail
authors: Elena
authors: E
authors: Pak
authors: Kavitha
authors: K
authors: Narayan
mesh_terms: D000276:Adjuvants, Immunologic / Q000627:therapeutic use*; D000328:Adult; D000906:Antibodies / Q000097:blood / Q000276:immunology*; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005188:False Negative Reactions; D005260:Female; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D016899:Interferon-beta / Q000276:immunology* / Q000378:metabolism / Q000627:therapeutic use*; D008297:Male; D009103:Multiple Sclerosis / Q000188:drug therapy* / Q000276:immunology*; D064547:Myxovirus Resistance Proteins; D012333:RNA, Messenger / Q000097:blood; D013997:Time Factors
chemical_list: D000276:Adjuvants, Immunologic; D000906:Antibodies; C579071:MX1 protein, human; D064547:Myxovirus Resistance Proteins; D012333:RNA, Messenger; D016899:Interferon-beta; D019204:GTP-Binding Proteins