[The immune system and primary headache syndromes].

The association between pain and inflammation and certain clinical signs led physicians to suspect a connection between immunological mechanisms and headache syndromes even years ago. This review intends to give an overview of the literature which deals with immunological mechanisms in headache syndromes--with divergent results. Thus, a food allergy as a cause of migraine only seems to be relevant in a few isolated cases. Immunoglobulins or infections do not seem to play a role. Whether the complement system, auto-antibodies, immune cells or cytokines are involved in migraine pathophysiology, still remains to be determined. With regards to cluster headache, a participation of the immune system seems more probable. Although a systemic vasculitis or auto-antibodies probably do not contribute to cluster headache pathophysiology, reports of an immune activation, especially of T-cells, predominate the literature. Nevertheless, the evidence for an immunogenically triggered cluster attack is still lacking. In summary, only a mutual modulation of the immune and the pain system can be assumed with certainty.