CX3CL1 and Headache: Serum levels of CX3CL1 were increased in the worsened (2145 [811–4866] pg/ml) and new onset (1668 [0-7357] pg/ml) headache group as compared to patients with no (1129 [0-5379] pg/ml) or unchanged (1478 [346–4332] pg/ml) headaches.