Tocilizumab therapy for IL-6 increment in a patient with non-fatal severe fever with thrombocytopenia syndrome.

We report the administration of an anti-interleukin (IL)-6 antibody in a case of severe fever with thrombocytopenia syndrome (SFTS) with an increase in IL-6. On the day of admission, SFTS viral load and IL-6 concentration were 93 831 copies/ml and 5.4 pg/ml, respectively, and tocilizumab was administered. SFTS viral load decreased to 17 821.1 copies/ml on the 3 day of admission, while IL-6 levels increased to 104.9 pg/ml; SFTS viral load and IL-6 levels had decreased to 2876.4 copies/ml and 48.2 pg/ml on 7 day of admission, respectively. The patient fully recovered no tocilizumab adverse events.