TLR8 and viral infectious disease: Since TLR8 (and TLR7) senses and responds to various kinds of RNA viruses (Marcken et al., 2019 ▸; Coch et al., 2019 ▸), TLR8 deficiency has been proposed to cause viral infections; however, it has been reported that TLR8 deletion accelerates autoimmunity in mice (Tran et al., 2015 ▸).