FAM26F RNA in PBMCs was quantified at defined time points along with MX1 and CXCL10. In all experiments, FAM26F transcripts were significantly elevated after SIV-infection as compared with pre-infection values until the end of the study period (P<0.0008 from week 2 up to weeks 32–48 post infection, Mann Whitney test, data for E1; Fig. 4). Here, MX1 is linked to infection.