Interferon-β antibodies have a higher affinity in patients with neutralizing antibodies compared to patients with non-neutralizing antibodies

In this study, we investigated the affinity, determined by a relative affinity assay, using increasing concentrations of sodium-isothiocyanate to disrupt the antigen antibody binding of neutralizing and non-neutralizing antibodies against interferon-β (IFNβ)-1a and -1b in 73 serum samples of MS patients treated with IFNβ-1a or -1b. Relative affinity values were significantly higher in NAB-positive compared to NAB-negative samples and in samples of IFNβ-1a-treated patients compared to IFNβ-1b. A significant positive correlation between relative affinity values and therapy duration indicates affinity maturation as another qualitative factor in IFNβ neutralization.