IFNAR1 and type 1 diabetes mellitus: Following infection with Kilham rat virus (KRV), T1D onset was preceded by KRV invasion into multiple splenocytes, a reduction in CD8+ T-cell numbers, and scRNA-seq results showing increased expression of MHC class II transcripts on monocytes and macrophages in type I IFN and IFN receptor (IFNAR)-loss rats.