IS THE UNRESPONSIVENESS TO SUMATRIPTAN IN CLUSTER HEADACHE RELATED TOAN ALTERATION IN THE 5-HT RECEPTORS

It is well established that cluster headache shows impaired functions at the neuroimmunomodulatory system level. Defects in the expression o f receptors for 5-HT, IL-1 and IL-2 have been found in these patients. Sumatriptan, an agonist activity for 5-HT1D receptor, truncates clust er headache attack in 74% of patients. Flow cytometric analysis of mon ocytes expressing 5-HT receptor in cluster headache patients showed di fferent trends clearly correlated with the clinical response to sumatr iptan. Our findings strongly support the concept that cluster headache patients which are non-responders to sumatriptan could present a bloc k in their 5-HT receptor expression possibly due to specific autoantib odies for this receptor site.