Aberrations in peripheral inflammatory cytokine levels in migraine: A systematic review and meta-analysis.

BACKGROUND:Migraine is the second most common neurological disorder. Inflammation plays an important role in the pathology and symptoms of migraine. Although, many studies have analyzed the levels of peripheral cytokines in migraine patients, the conclusions of these studies were not consistent. Meta-analysis for peripheral cytokine levels in migraine is necessary to solve the inconsistency in clinical conclusion. METHODS:We conducted a systematic search to July 2021, to identify the literatures that measured peripheral cytokine levels in migraine patients and compared them with healthy controls. RESULTS:10 studies were finally included in the meta-analysis: 6 for C-reactive protein (CRP), 2 for interleukin (IL)-1β, 5 for IL-6, 3 for tumor necrosis factor alpha (TNF-α), 1 for IL-2, 2 for IL-10. Compared with healthy controls, we found that the patients with migraine had higher serum levels of CRP (standardized mean difference, SMD = 1.48; P < 0.001), IL-1β (SMD = 0.75; P < 0.001), IL-6(SMD = 1.18; P<0.001) and TNF-α (SMD = 0.69; P = 0.003), while did not have significant difference in serum IL-2(SMD = -0.24; P = 0.25) and IL-10 (SMD = -0.17; P = 0.88). CONCLUSIONS:The findings of the meta-analysis provide evidence for higher serum of CRP, IL-1β, IL-6 and TNF-α in migraine patients compared with healthy controls. Our results support that inflammation play a role in the pathophysiology of migraine. However, there was no significant difference in serum IL-2 and IL-10.