Analysis of virus-specific immunological response and clinical study trial for severe fever with thrombocytopenia syndrome(SFTS)

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K09935
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Infectious disease medicine
• Research Institution: Ehime University
• Principal Investigator: Suemori Koichiro 愛媛大学, 医学部附属病院, 講師 (80571083)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: SFTS / ファビピラビル / 異型リンパ球

Outline of Final Research Achievements

Severe fever with thrombocytopenia syndrome (SFTS) was first reported as an novel tick-born infection with a high-fatality rate during 2011 in China.SFTS has been reported to be endemic in Japan since 2013. Pathopysiology and treatment of SFTS is unclear. Recently,it was reported that the anti-viral drug (favipiravir)inhibits the replication of SFTS virus in mouse model. Therefore, we have conducted a multicenter non-randomized trial,in which all patients with SFTS would receive favipiravir since 2016.The results implied the efficacy and safety of favipiravir against SFTS patients. On the other hand,we analyzed atypical lymphocytes in the peripheral blood in four SFTS patients at our hospital.Atypical lymphocytes resembled plasma cells morphologically and showed a CD19+CD38+ phenotype in flow cytometry. Our result suggests that specific immunological response occurs at SFTS infection.

Free Research Field

感染症

Academic Significance and Societal Importance of the Research Achievements

致死率が高く、治療法が確立されていない重症熱性血小板減少症候群 (SFTS) に対するファビピラビルの有効性および安全性を世界で初めて臨床研究を行い検証した。近年、本邦におけるSFTSの真の死亡率は25～30%と指摘されているが、ファビピラビル投与群での死亡率は17.4%であり、ファビピラビルの有用性が示唆された。また本病態には支持療法の重要性も示唆され、当院における末梢血における異型リンパ球の表現型解析は、SFTSに対する特異的免疫応答を理解する上で重要な結果であり、病態把握や今後の支持療法の確立に役立つ可能性がある。