IL4 and infection: Taken together, the upregulation of MMPs in the PCMP-treated extremities provides evidence of infection clearance, including the recruitment of immune cells by MMP-1, -2, -7, and -9, the activation of defensins to kill MRSA by MMP-7, and the dampening of excess MMPs through the upregulation of IL-4 and IL-10 [28,38].