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Background: Some multiple sclerosis (MS) patients treated with interferon beta (IFN beta) develop antibodies to the drug. Neutralising antibody (NAB) assays for IFN beta are expensive and the clinical relevance of the results has been debated.Objective: To establish a cheap, sensitive, and reliable assay for antibodies to (125)I-IFN beta, and to correlate levels of antibodies with clinical response to IFN beta treatment.Methods: We established a radioimmunoprecipitation assay (RIPA) using (125)I-IFN beta. We tested NAB positive sera, healthy control sera, and serial samples of 33 IFN beta-1b treated MS patients from the Vancouver cohort of the Berlex pivotal trial who had a high incidence of NABs.Results: We found that the RIPA was highly sensitive for the detection of antibodies to IFN beta-1a and -1b, and that there was a strong correlation between reactivity of NAB positive sera for (125)I-IFN beta-1b and for (125)I-IFN beta-1a. The RIPA was more sensitive and consistent than the NAB. Moreover, there was a trend towards poorer MRI outcomes in RIPA positive patients, but not in NAB-positive patients.Conclusions: The RIPA assay is sensitive and easy to perform. It should be of value in assessing the clinical impact of IFN beta antibodies, and its use could help target expensive INF beta treatments to those who will respond best. [ABSTRACT FROM AUTHOR]

The article focuses on long lasting antalgic effects of daily repetitive transcranial magnetic stimulation in neuropathic pain. A predictive test to improve outcome would have been invaluable in selecting patients for such procedures. In a study, procedures. Transcranial magnetic stimulation (TMS) in single sessions were reported to have a predictive effect. However, it goes further. Prolonged and significant pain relief can be achieved with repetitive TMS. In this series the majority had head, face, and arm pain, either from trigeminal neuralgia or stroke. This may well establish higher frequency TMS as an effective methodology of screening patients for implantation of motor cortex stimulation and since the effects are rather prolonged, may even prove to be a methodology that may be useful as an outpatient treatment for certain pain patients.