Expression of interferon type-I receptor isoforms, clinical response and development of neutralizing antibodies in multiple sclerosis patients – results of a prospective study

Background: One of the first line treatments for relapsing-remitting multiple sclerosis (RRMS) is interferon-beta (IFNb), a cytokine with immune-modulatory effects. There is a high degree of variability in the response to the drug which is, among other factors, due to the presence of neutralizing antibodies (NABs) occurring late during therapy. Methods: The objective of this study was to determine whether the response to IFNb therapy and NAB development can be predicted based on the expression levels of the type-I interferon receptors IFNAR1, IFNAR2a, IFNAR2b, and IFNAR2c before start of treatment. The IFNAR expression levels in 163 samples of patients with relapsing-remitting MS were measured by real-time polymerase chain reaction (PCR). Results: Pre-treatment IFNAR2c expression levels were somewhat lower in patients who developed NAB during treatment compared to NAB-negative patients. No significant differences in the expression levels of other IFNAR subtypes and isotypes were found. Baseline IFNAR levels were not predictive of the clinical response after 2 years. Conclusions: Overall, there was a small, non-significant effect of IFNAR2c baseline levels on NAB development but no relation to clinical endpoints. Lower expression of IFNAR2c receptors could lead to higher IFNb levels inducing a higher rate of antibody response.