RETNLB and Stroke: qPCR analysis of the PI area in the stroke brains at 3 dpi revealed a significant increase of major alternative activation markers Arg1 (Fig. 4a, p = 0.0408) and Ym1 (Fig. 4b, p = 0.0122), but not Fizz1/Rentla (data not shown) upon IL-13 treatment.