To test whether T helper 17 (Th17) cells was involved in the pathogenesis of multiple sclerosis (MS) by conducting a meta-analysis of the researches documenting the levels of Th17 cells and Th17-related cytokines [interleukin (IL)-17, IL-23] in patients with MS.

We identified articles reporting proportion of Th17 cells and the serum levels of IL-17, IL-23 in MS patients by searching CNKI, Wanfang med online, Embase, PubMed, Cochrane, WebofKnowledge, Food and Drug Administration (FDA). gov, and ClinicalTrials.gov. We registered this study at the International Prospective Register of Systematic Reviews (PROSPERO) (number CRD42017059113). The evidence level of selected studies was identified by guidelines from the Oxford Center for Evidence-Based Medicine 2011. We employed the Newcastle-Ottawa Quality Assessment Scale (Case Control Studies) to perform the included resear. Stata 12.0 was adopted for processing Meta-analysis of the data by using a random effects model.

A total 16 researches were included in our Meta-analysis from 587 identified studies. The proportion of Th17 cells [1.89%(1.10%, 2.69%),P<0.01] and the levels of serum IL-17 [2.77(1.77, 3.77) pg/ml, P<0.01] and IL-23 [2.96(1.51, 4.40) pg/ml, P<0.01] increased dramatically in MS individuals compared with control subjects.

The results of this Meta-analysis has demonstrated that MS patients have a higher proportion of Th17 cells in higher levels of serum IL-17 and IL-23 compared to control subjects, which has demonstrated that Th17 cells may play an vital role in the pathogenesis process of MS patients.

Multiple sclerosis; T helper 17 cells; Iinterleukin-17; Iinterleukin-23