Abstract 106: Circulating Interleukin-6 Levels Early During Active Stroke Estimate Time of Stroke Onset: Potential New Clinical Biomarker Tool From a Mobile Stroke Unit

• Published in: Stroke (1970) Vol. 55; no. Suppl_1
• Main Authors: Kowalski, Robert G, Ledreux, Aurelie, Violette, John, Neumann, Robert, Grotta, James C, Ornelas, David, Thompson, John A, Monte, Andrew, Dylla, Layne, Coughlan, Christina, Yu, Xiaoli, Graner, Michael, Jones, William
• Format: Journal Article
• Language: English
• Published: 01.02.2024
• ISSN: 0039-2499; 1524-4628
• DOI: 10.1161/str.55.suppl_1.106

Abstract only Background: Circulating interleukin-6 (IL-6) concentrations are elevated in acute stroke but the timing of the IL-6 response in humans is unknown. We used a mobile stroke unit (MSU) to identify IL-6 levels within minutes of symptom onset. The results suggest a tool for estimating onset time for nearly 200,000 stroke patients annually in the U.S. in whom this is unknown. Methods: The study is a prospective, cohort investigation of ultra-early blood-derived IL-6 in acute stroke. Blood was obtained on the MSU, at 24 hours, and from hospital stroke patients and healthy controls. Plasma IL-6 was analyzed with ELISA. Confirmed strokes, mimics and controls were compared. Variables included demographics, DWI lesion volume, mRS, and NIHSS. Results: Forty-two adults were analyzed, including 28 patients treated on the MSU between August 2021 and May 2023, and 14 controls. Nineteen (68%) MSU patients were diagnosed as stroke, with 17 (61%) confirmed and 2 likely TIA or stroke averted by thrombolysis; 9 were stroke mimics. For confirmed stroke patients, median age was 72 (range 36-87) years, 47% were female, and 82% white. Median initial NIHSS score was 7 (range 1-22) and 12 (71%) received intravenous thrombolysis with tPA or TNK. Blood was obtained a median of 57 (range 26-158) minutes after symptom onset. IL-6 was elevated in all 17 confirmed stroke patients, a median of 3 times normal, as early as 26 minutes after symptom onset (median 6.4 pg/mL). In 15 (88%) cases, IL-6 increased over 24 hours, (median Δ 8.9 pg/mL). For mimics and healthy controls, median IL-6 was 5.9 and 2.3 pg/mL, respectively. Initial IL-6 in strokes was not associated with lesion volume (Spearman’s r= -0.035, p=894) or initial NIHSS (Spearman’s r=-0.043, p=869). Based on IL-6 trajectories observed, a cutoff for IL-6 set at 8 pg/mL had a sensitivity of 79% and specificity of 36% for estimating the stroke onset time was in the 4.5-hour thrombolysis window. Conclusions: This study found IL-6 was elevated in all confirmed strokes and increased in a linear fashion during the first 2.5 hours. IL-6 was independent of lesion volume and NIHSS. This suggests a rapid measurement of IL-6 from blood early in acute stroke may estimate onset time. The findings may aid development of immunomodulatory therapies for IL-6 in acute stroke.