Complement and Immune Complex Studies in Migraine

SYNOPSIS Serum complement component levels were measured in sera from those migraineurs who experience premonitory focal neurological symptoms (prodromal) and immune complexes were sought in sera from both prodromal and non‐prodromal migraineurs. Comparison was made between headache‐free, onset and late headache samples in these determinations. Serum complement component levels were shown not to change with migraine, in prodromal migraineurs. This contrasts with non‐prodromal migraineurs in whom we have previously reported complement activation via the classical pathway at the onset of headache. Classical pathway activation of complement is most commonly initiated by immune complexes and these were sought using a CIq precipitation technique. Circulating immune complexes were only detected in sera from non‐prodromal migraineurs. In this group of patients there was a significant correlation between the presence of immune complexes and the onset of headache. These results indicate the occurrence of an immune reaction at the headache onset in non‐prodromal migraineurs but not in prodromal migraineurs. An immune complex mediated immune response could account for many of the reported phenomena in migraine including platelet aggregation and 5‐HT release and basophil and mast cell degranulation. The timing and transient nature of the immune reaction argues for its having a causative role in the attacks of migraineurs without prodromes.