Various immunological studies have revealed controversial outcomes on pathogenetic mechanisms of food-induced migraine. In order to better define the immune status of this disease we studied 21 patients for circulating immune complexes (CIC). Six out of them were also studied for lymphocyte subpopulations, IgG 4 and anti-IgG antibodies, before (TO), 4 hours after (T4), and 72 hours after (T72) a specific challenge with 250 ml of milk. The CIqSp assay was used to determine CIC. Lymphocyte subpopulations were defined by the following monoclonal antibodies (Mab): OKT3, OKT4, OKT8, 4F2, H366, TAC, 5E9, L.243 and DA6.231. IgG 4 subclass was assessed by using a mouse specific Mab. Anti-IgG antibodies were determined by using HPLC.

The result showed an increased incidence of CIC (28.6%) when compared to the control group (10%). Total T-cells (OKT3 + ) showed a marked increase at T4 (p<0.01 ) and a subsequent decrease at T72 (p<0.02). Interestingly, T-activated cells (4F2 + and TAC + ) showed a parallel trend at T4 (respectively p<0.02 and <0.01) and a subsequent decrease at T72 only for the Tac+ cells (p<0.05). Also K and NK cells (H366+) showed an early increase at T4 (p<0.05). No significant variation was observed in the study of the expression of DR anti-gens (L.243 and DA6.231) at the three times. IgG 4 and anti-IgG antibodies values showed no variation in their time-course.

In commenting on the outcomes of this investigation, it must be stressed that the evidence of an early lymphocyte activation after the challenge test indicates an involvement of Interleukin-2 related receptors in food-induced migraine. The results have reinforced the idea of an immune mechanism involvement in food-induced migraine, but it seems to be localized at a different step from that until now hypothesized.