IFNA1 and viral infectious disease: However, this hypothesis remains to be formally demonstrated in vivo, and several remaining questions remain to be resolved, including (i) how pDCs discriminate infected macrophage sentinels from their uninfected counterparts in the spleen and LNs, (ii) whether specific endocytic receptors are involved in material transfer from infected macrophages to pDCs, and (iii) whether other microanatomical niches exist in body barrier tissues to promote local pDC IFN production during peripheral viral infections.