Neutralizing antibodies to interferon (IFN) alpha-2a and IFN beta-1a or IFN beta-1b in MS are not cross-reactive.

Sera from patients with MS treated with recombinant interferon (rIFN) alpha-2a, rIFNbeta-1a, or rIFNbeta-1b were analyzed for cross-reacting neutralizing antibodies (NAB). Because cross-reactivity was not found, switching treatment from rIFNbeta-1a or rIFNbeta-1b to rIFNalpha-2a might provide a secondary treatment response in patients with NAB to rIFNbeta-1a or rIFNbeta-1b. A positive treatment response also might be achieved by switching NAB rIFNalpha-2a-positive patients to rIFNbeta-1a or rIFNbeta-1b.