Molecular detection of interferon-α expression in multiple sclerosis brain

The demonstration of intermittent interferonaemia in patients with multiple sclerosis prompted a molecular analysis of brain tissue for expression of interferon-α genes. A sensitive method was developed based on the polymerase chain reaction. Primer sets were used that could amplify all interferons-α or two particular subtypes, interferon-α2 and interferon-α4. The procedure was successful in detecting expression of interferons-α in brain and non-brain tissues in most patients with multiple sclerosis. However, expression was demonstrable also in a similar proportion of patients with other neural diseases, and patients with other illnesses. The data indicate that there can be constitutive expression of interferons-α in brain tissue, but the possibility that this becomes amplified in multiple sclerosis was not revealed by this study.