Neurogenic inflammation is considered as an animal model of human migraine attacks. Using flow cytometry, we examined T-cell subsets and their integrin expression in the peripheral blood of 32 migraine patients in order to evaluate a possible inflammatory process in humans, as postulated in the migraine animal model. Our results show that migraine patients have a significant increased proportion of T-helper (47.4 +/- 6.3% vs 43.2 +/- 5.8%; p < 0.01) and T-helper memory cells (23.6 +/- 5.9 vs 20.3 +/- 6.5%; p < 0.01). Moreover, the 22 migraine patients without aura also exhibited an increase of LFA-1 expression of T-helper cells (34.7 +/- 11.5%) compared to the 35 controls (27.5 +/- 12.0%; p < 0.01). These preliminary results support the hypothesis that immunological mechanisms (such as an enhanced lymphocyte endothelium interaction) could be part of the migraine pathophysiology in humans.