JAK3 and Stroke: Inhibiting JAK3 appears to be a double-edged sword in the acute phase of ischemic stroke; although it has the ability of reducing IL-17A mRNA transcription by γδT cells and IL-21, which have been shown to be detrimental in stroke (8, 23), it is also blocking potential IL-4 signaling in neurons, which is neuroprotective in the ischemic brain (24).