Serum Interleukin-37 Increases in Patients after Ischemic Stroke and Is Associated with Stroke Recurrence

Background This study seeks to assess interleukin-37 (IL-37) serum level in acute ischemic stroke and the value of predicting 3-month stroke recurrence and functional outcome in acute ischemic stroke. Methods From January 1, 2018, to June 30, 2019, all consecutive first-ever acute ischemic stroke patients from our hospital, China, were included. Serum samples, clinical information, and stroke severity (defined by the National Institute of Health stroke scale (NIHSS) score) were collected at baseline. Serum IL-37 level was measured by the enzyme-linked immunosorbent assay (ELISA) method. Functional impairment (defined by the modified Rankin scale (mRS)) and recurrent stroke were assessed 3 months after admission. The relation of IL-37 with either clinical severity at baseline, unfavorable functional outcome, or stroke recurrence at follow-up was evaluated by logistic regression analysis, and the results were presented as odds ratios (OR) with 95% confidence intervals (CI). Results Three hundred and ten stroke patients were included. The median IL-37 serum level in those patients was 344.1 pg/ml (interquartile range (IQR), 284.4-405.3 vs. control cases: 122.3 pg/ml (IQR, 104.4-1444.0); P 405.3 pg/ml) was still associated with recurrent stroke (OR = 3.32; 95%CI = 2.03-6.13; P < 0.001). IL-37 could promote the NIHSS score (area under the curve (AUC) of the IL-37/NIHSS, 0.75; 95% CI, 0.67-0.83; P < 0.001), corresponding to a difference of 0.085 (0.005). Serum IL-37 increases in patients with poor outcome, and an IL-37 in the highest quartile is related to poor outcome (OR = 4.85; 95%CI = 3.11 - 8.22; P < 0.001). Conclusion Serum IL-37 increased in patients after ischemic stroke and was associated with stroke recurrence events and poor stroke outcomes. Large randomized controlled trials should be carried out to confirm whether IL-37 lowering treatment improves stroke prognosis.