Association between Serum IL-37 and Spinal Cord Injury: A Prospective Observational Study

Objective: Interleukin-37 (IL-37) is a new cytokine that naturally inhibits inflammation. Inflammation plays an important role in acute spinal cord injury (SCI). The purpose of this study is to check whether serum IL-37 can be used as a clinical predictor of SCI.

Methods: All subjects underwent venipuncture within 24 hours of enrollment to obtain peripheral blood and then centrifuged to obtain serum. The concentration of serum IL-37 was determined by enzyme-linked immunosorbent assay (ELISA). One month after the injury, the American Spinal Cord Injury Association (ASIA) impairment scale was used for neurological examination.

Results: A total of 148 people were included in the study, including 52 normal controls (NC) and 96 patients with acute SCI within 24 hours of onset. The comparison of clinical baseline data (age, gender, BMI: body mass index, smoking, alcohol drinking, CHD: coronary heart disease, HBP: high blood pressure, and DM: diabetes mellitus) between the two groups was not statistically significant (p > 0.05). However, the serum IL-37 concentration of SCI patients was significantly higher than that of the NC group, and the difference was statistically significant (p < 0.001). And with the aggravation of SCI grade, the level of IL-37 increased significantly (p < 0.05). Pearson correlation analysis further showed that serum IL-37 concentration is negatively correlated with AISA motor score (r = -0.327, p < 0.05).

Conclusion: The serum IL-37 concentration of SCI patients is significantly increased, and it is closely related to the recovery of motor function. We proved for the first time that serum IL-37 has prognostic value in patients with SCI. In addition, serum IL-37 may be used as a prognostic biomarker for SCI.