The cause of migraine is unknown but there is circumstantial evidence to suggest that immune mechanisms may be involved in its pathogenesis: several workers have noted an increased incidence of allergy in patients with the disease and the migraine which accompanies the ingestion of specific foods has also been explained on an allergic basis. In a recently reported study investigators detected evidence of activation of the serum complement system during migraine headache, with significant reductions in complement factors C4 and C5, and the appearance of C3 breakdown products.

We therefore studied 40 patients, who included 10 subjects in the acute and quiescent phase of the disease. We measured complement components CIq, C4, C3, C7 and Factor B, together with the conversion products of C3 and Factor B. CH 50 units were also estimated and anti complementary activity was assayed. No abnormalities were detected in any of the patients either in an attack or during a remission. Thus, our results do not confirm that complement activation plays a role in migraine headache.