Study of binding and neutralising antibodies to interferon-β in two groups of relapsing-remitting multiple sclerosis patients.

Abstract

Interferon (IFN)-β is generally considered an effective treatment for multiple sclerosis (MS); however, some patients do not respond to this therapy, possibly due to the production of neutralising antibodies (NAB) which can prevent the biological effect of IFN-β. We compared the two types of IFN-β, the glycosylated IFN-β1a and the non-glycosylated IFN-β1b, as their chemical differences may entail differing immunogenic capacities. We studied 22 relapsing-remitting MS patients treated with IFN-β1a and 31 treated with IFN-β1b for 1 year, using the same assay and criteria, to compare the two types of IFN-β in their ability to induce binding and neutralising antibodies and examined the correlation of the findings with the clinical data. Binding antibodies to IFN-β1a and IFN-β1b were determined by enzyme-linked immunosorbent assay. A bioassay was used to detect and quantify the NABs to IFN-β, measuring the capacity of NABs to block the antiviral resistance induced by IFNs. Binding antibodies were found in 32% of those treated with IFN-β1a and in 52% of those treated with IFN-β1b; NABs were found in 14% and 24%, respectively. Both groups showed a significant decrease in relapse rate during the first year of treatment. These results demonstrate that the IFN-β1b molecule is more immunogenic than the IFN-β1a molecule. This may be due to the non-glycosylated, chemical structure of the former, which can produce aggregates and enhance antibody production. No association was found between the presence of NABs and the clinical status of the patients.