Effector memory (TEM) CD4+T cells (CCR7–CD45RA–) (median 49.2% of CD4+T cells) are typically observed in patients with mild/moderate HFRS, while the individuals with severe/critical disease were enriched for central memory (TCM) CD4+T cells (CCR7+CD45RA–) (median 50.2% of CD4+T cells) (Fig 8B). Here, CCR7 is linked to hemorrhagic fever with renal syndrome.