Neutralising antibodies against interferon-beta


For monitoring of interferon-beta (IFN-beta) treatment and test for neutralising anti-drug antibodies (NAbs).

All IFN-beta-based drugs can be tested:

  • Avonex (IFN-beta 1a)
  • Betaferon (IFN-beta 1b)
  • Rebif (IFN-beta 1a)

Test result

Results are given as positive or negative.


The assay is based on an in vitro reporter cell (iLite), which tests whether the antibodies in patient serum can prevent IFN-alpha/ IFN-beta from signaling via IFN-alpha receptor 1 (IFNAR1 ) expressed on the cell surface. The signals from IFNAR1 activate a reporter gene (Firefly Luciferase) and the effect of the produced enzyme can be measured in an instrument.

The method is very stable and repeatable and based on a cell cycle arrest and the cells can therefore be used straight from the freezer.

The sample should be taken when the concentration of the drug is expected to be as low as possible (the "Cmin at steady state" or "trough" levels). "Cmin" corresponds to the minimum drug concentration at "steady state" when the variation of drug concentration in the serum is the lowest and provides the highest sensitivity for detection of NAbs. 

Any NAbs cross-react between the drugs within the same interferon subgroup.

Relevance and result interpretation

rIFN-beta is well known for the treatment of multiple sclerosis (MS). Presence of NAbs against IFN- beta is well known and has been shown to be associated with reduced treatment response, increased number of relapses, increased MRI activity and an increased disease progression.

The treated patient cannot switch to alternative IFN-beta treatment if NAbs against IFN-beta have developed since NAbs cross-react between the drugs.

More information is given here.

Read more about sampling

Packages and other tests

. View other tests Neutralising antibodies against interferon-alpha

Acute test