For B cells, three traits were linked with increased ischemic stroke risk: B‐cell activating factor receptor (BAFF‐R) on IgD + CD38– unswitched memory B cells (IVW: odds ratio [OR] 1.04, 95% confidence interval [CI] 1.01–1.07; p = 0.018), CD27 on CD20– CD38– B cells (IVW: OR 1.05, 95% CI 1.01–1.10; p = 0.027), and CD38 on IgD+ CD24– B cells (IVW: OR 1.09, 95% CI 1.01–1.18; p = 0.032). Here, TNFRSF13C is linked to ischemic stroke.