CCL2 and migraine disorder: Many correlative relationships between PA-1 and other cytokines are found: positive with MMP-9 (rS = 0.77), TGF-α (rS = 0.82), and MCP-1 (rS = 0.33), and negative one with sICAM-1 (rS = −0.72) in migraine patients without aura (Figure 5B).