Transient Appearance of Plasmablasts in the Peripheral Blood of Japanese Patients With Severe Fever With Thrombocytopenia Syndrome.

Atypical lymphocytes in the peripheral blood in patients with severe fever with thrombocytopenia syndrome (SFTS) have not been well examined. In this study, we analyzed counts and characteristics of atypical lymphocytes in 7 patients with SFTS. Atypical lymphocytes resembled plasma cells morphologically and appeared in the peripheral blood of all patients 4-8 days after onset of disease.