Our previous study (27) showed that expression levels of type I IFNs, including IFNA and IFNB, type II IFN IFN-γ, and the ISGs MX, IFITM1, and OSAL were all upregulated in peripheral-blood lymphocytes of SPF chickens in the early stage of ARV infection and peaked 3 days after infection. Here, IFNA1 is linked to infection.