Recently, PD-L1 and PD-L2 upregulation has been demonstrated in monocytes exposed to Brugia malayi, the causative parasitic agent for filariasis (64), indicating that the effect on PD-L1/2 in phagocytic APCs may be part of an immune-regulatory pathway employed by different parasites. This evidence concerns the gene PDCD1LG2 and filariasis.