title: [Long-term effect of neutralizing antibodies to interferon beta-1 b in patients with multiple sclerosis].
abstract: OBJECTIVE
  Our goal was to evaluate the relation between the presence of neutralizing antibodies (NABs) to interferon beta-1b in multiple sclerosis (MS) patients and the clinical evolution in the following years.
  
  
  METHODS
  As we previously reported, we tested NABs in 68 patients treated with interferon beta-1b after 2 years of treatment. We prospectively followed this cohort every three months for a minimum period of 6 years collecting data about relapses, disability, secondary effects and dropouts.
  
  
  RESULTS
  During the 6 year follow-up period, the annualized relapse rate did not differ between patients with and patients without NABs. A sustained progression was observed in 33% of positive patients and in 38% of patients without NABs. No differences were found in the proportion of patients who reached an EDSS score of 6. Secondary effects were similar in both groups.
  
  
  CONCLUSIONS
  Although our results do not vouch for a negative effect of the presence of NABs on the clinical evolution of MS patients treated with interferon beta, further longitudinal studies to clarify the real effect of the presence of NABs in these patients are still much needed.
authors.affiliation: Unitat de Neuroimmunologia Clínica, Hospital Universitari Vall d'Hebron, Barcelona, Spain. jrio@vhebron.net
authors.forename: Jordi
authors.initials: J
authors.lastname: Río
authors.forename: Mar
authors.initials: M
authors.lastname: Tintoré
authors.forename: Nieves
authors.initials: N
authors.lastname: Téllez
authors.forename: Carlos
authors.initials: C
authors.lastname: Nos
authors.forename: Ingrid
authors.initials: I
authors.lastname: Galán
authors.forename: Xavier
authors.initials: X
authors.lastname: Montalbán
mesh_terms: D000276:Adjuvants, Immunologic / Q000627:therapeutic use*; D000906:Antibodies / Q000097:blood*; D000917:Antibody Formation; D005500:Follow-Up Studies; D006801:Humans; D000068576:Interferon beta-1b; D016899:Interferon-beta / Q000276:immunology / Q000627:therapeutic use*; D009103:Multiple Sclerosis / Q000188:drug therapy* / Q000276:immunology*; D009500:Neutralization Tests; D013997:Time Factors
chemical_list: D000276:Adjuvants, Immunologic; D000906:Antibodies; D000068576:Interferon beta-1b; D016899:Interferon-beta