CCL4 and type 2 diabetes mellitus: To this end, our data show that the increased fractalkine levels in T2D patients (Fig. 2a–d) were positively correlated with systemic concentrations of CCL3 (r = 0.52, P = 0.013), CCL4 (r = 0.85, P < 0.0001), CCL11 (r = 0.51, P = 0.01), and CXCL1 (r = 0.67, P = 0.0005).