PUTATIVE NEUROIMMUNOLOGICAL MECHANISMS IN CLUSTER HEADACHE - AN INTEGRATED HYPOTHESIS

During the last decade, numerous studies have been carried out to expl ore the function of the immune system in cluster headache and the rele ase of reciprocal informational molecules from pain-sensitive structur es. These neuroimmunological findings in cluster headache syndrome, al though carefully considered, have varied from genetic aspects (HLA ant igens) to functional activity of the immune system (NK cytotoxicity), and from study of the receptor expression of classical neurotransmitte rs of pain (5-HT, histamine) on immunocompetent cells, to the study of cytokines with a potent pro-inflammatory activity (interleukin-1). Ot her aspects considered have ranged from the study of the effectiveness of substances possessing a well-known activity on the immune system ( prednisone, lithium carbonate) in shortening cluster attacks to the 5- HT receptor expression changes observed on a peripheral substrate (mon ocytes) after the administration of sumatriptan, Although this was an exciting area of pioneering research, we have always interpreted our f indings cautiously. In summary, we now believe that the neuroimmunolog ical aspects of cluster headache can be proposed as an integrative mod el and that this immunological mechanism could improve our understandi ng of the pathogenic basis for this still obscure disease.