IFNA1 and infection: Overall, the data suggest that: (1) IFN-α is a crucial mediator of hematological symptoms in LCMV-cl13 infections, not only through its direct impact on HSCs, but also as a critical activation signal for virus-specific CD8 T-cells, causing immunopathological destruction in HSCs and stroma; and (2) HSC niche support of the BM microenvironment is impaired, resulting in a long-term impairment in HSC activity that is essentially uncoupled from the initial proliferative burst.