Hantaviruses are zoonotic RNA viruses that cause severe acute disease in humans . Infected individuals have strong inflammatory responses that likely cause immunopathology . Here, we studied the response of mucosal-associated invariant T (MAIT) cells in peripheral blood of individuals with hemorrhagic fever with renal syndrome (HFRS) caused by Puumala orthohantavirus, a hantavirus endemic in Europe . We show that MAIT cell levels decrease in the blood during HFRS and that residual MAIT cells are highly activated . This activation correlates with HFRS severity markers . In vitro activation of MAIT cells by hantavirus-exposed antigen-presenting cells is dependent on type I interferons (IFNs) and independent of interleukin-18 (IL-18). These findings highlight the role of type I IFNs in virus-driven MAIT cell activation and suggest a potential role of MAIT cells in the disease pathogenesis of viral infections.
Index: IL-6, MAIT cells, Puumala orthohantavirus, T cells, cytokines, endothelial cells, hantavirus, hemorrhagic fever with renal syndrome, monocytes, type I interferons