PDCD1 and disease arising from reactivation of latent virus: Interestingly, while lowly-expanded cells in both chronic and latent infections were preferentially located in this Tcf7+ Il7r+ Slamf6+ cluster (cluster 7) (Figures 5B, C), a direct comparison of gene expression between stem-like cells in chronic and latent infection demonstrated that T cells arising from chronic infection maintain relatively higher expression of exhaustion markers (Pdcd1, Tox, Lag3) compared to Tcf7+ T cells from latent infection that maintained higher levels of Gzmm and Ifngr1 (Supplementary Figure S6).