CCL5 and intervertebral disk degenerative disorder: Given our data demonstrating common expression of genes with this pathway (Ccl5, Ccr5, Cfl1) that overlap with those induced by IL-4, mechanistic studies aimed at understanding the role of Ccl5/Ccr5 signaling within macrophages, the specific functions of this macrophage subset, and the downstream effects on disc degeneration are warranted.