At 4 weeks of age (before stroke onset), the plasma level of IL-1β was significantly higher in SHRSP (153.0 ± 49.7 pg/ml) than in Wistar Kyoto rats (WKY) (7.7 ± 3.4 pg/ml, P < 0.001 versus SHRSP) or spontaneously hypertensive rats (SHR) (28.0 ± 9.1 pg/ml, P < 0.001 versus SHRSP) (n = 6 per strain). Here, IL1B is linked to stroke disorder.