ABSTRACT
INTRODUCTION: Interferon-beta (IFNß) is currently the most used disease-modifying treatment for relapsing-remitting multiple sclerosis (RRMS), but it can lead to the production of neutralising antibodies (NABs) against IFNß. CLINICAL CASE: A lady with a past history of genital herpes was diagnosed with RRMS, started IFNß treatment with a good initial response. Three years later her treatment was interrupted to become pregnant. After delivery she restarted IFNß; she had more reactivations of genital herpes and experienced intermittent sensory symptoms often coinciding with herpes reactivation. High NABs titres against IFNß were found. Since the introduction of famciclovir as prophylactic antiviral therapy and a switch from IFNß to glatiramer acetate, herpes reactivations ceased and she had no further MS relapses. CONCLUSION: Exacerbations of genital herpes coinciding with MS relapses suggest a potential link between the development of NABs and inhibition of anti-viral action of endogenous IFNß. This case highlights that NABs not only decreases exogenous IFNß treatment efficacy, but may also interfere with anti-viral properties of endogenous IFNß. Investigating patients who are treated with biological medication will allow us to better understand the biology and signalling pathways in humans.
