Modulation of IFNAR1 mRNA expression in multiple sclerosis patients.

Interferon-beta receptor (IFNAR) is composed of 2 subunits, IFNAR1 and IFNAR2, the latter of which is expressed as functional (IFNAR2.2), non-functional (IFNAR2.1) and soluble (IFNAR2.3) isoform. Real-Time PCR analysis of mRNA for all IFNAR components in multiple sclerosis patients naïve for therapy and undergoing long-term treatment with interferon-beta shows that IFNAR1 mRNA level is lower than in healthy controls. If long-term treated patients are divided according to the production of mRNA for Myxovirus protein-A, a marker of interferon-beta bioactivity, IFNAR1 mRNA reaches the values observed in controls only in Myxovirus protein-A-induced patients. Since chronic cell stimulation by interferon-beta induces IFNAR protein down-regulation, we suggest that the increase of IFNAR1 mRNA might serve as a mechanism for counterbalancing the loss of protein receptor, enhancing, at least in this sub-group of patients, cell responsiveness to interferon-beta.