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MxA protein assay for optimal monitoring of IFN‐β bioactivity in the treatment of MS patients
Author(s) -
Vallittu A.M.,
Erälinna J.P.,
Ilonen J.,
Salmi A. A.,
Waris M.
Publication year - 2008
Publication title -
acta neurologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.967
H-Index - 95
eISSN - 1600-0404
pISSN - 0001-6314
DOI - 10.1111/j.1600-0404.2007.00968.x
Subject(s) - medicine , pharmacology , chemistry
Objectives – Myxovirus resistance protein A (MxA) can be used as a marker of the bioactivity of interferon‐beta (IFN‐β) therapy. Two to forty per cent of IFN‐β‐treated multiple sclerosis (MS) patients develop IFN‐β‐neutralizing antibodies (NAb) with subsequent attenuation of MxA protein induction. The aim of this study was to set up a simple MxA enzyme immunoassay (EIA) for the measurement of MxA protein and to evaluate the EIA test by comparing the results with flow cytometric analysis and the measurement of NAb. Methods – total of 51 IFN‐β‐treated relapsing–remitting MS (RRMS) patients were tested for MxA protein expression by using both MxA EIA assay and flow cytometric analysis. Thirteen patients were confirmed to be NAb‐positive. Results – The correlation between EIA and flow cytometric analysis was significant with a wider range of measured levels in the EIA. Patients with NAb had low MxA levels, but in some patients, remaining MxA induction could be detected despite NAb. Conclusions – The MxA EIA assay seems to be a practical method for large‐scale analysis of the bioactivity of IFN‐β treatment.