Fig. 3

Kinetics of peripheral B-cell subsets during acute phase of SFTS. a FACS gating strategy to define B-cell subsets by CD27 and IgD. b Schematic presentation of the relative composition of B-cell subsets in total peripheral B cells in the 3-week period post symptom onset. IgD⁻CD27⁺, IgD⁻CD27⁺⁺, IgD⁺CD27⁺, IgD⁻CD27⁻ and IgD⁺CD27⁻ represent memory, plasmablast, marginal zone-like, double negative and naive B-cell subsets respectively. HC = healthy control. c–g Kinetics of the proportion (upper) and numbers (lower) of B-cell subsets in total B cells and comparison of each subset between survived and deceased patients. Black triangles, red circles and blue horizontal lines represent means of survived, deceased and HC group, respectively. Statistic analysis was conducted between the survived and deceased groups. h FACS gating strategy defining IgG, IgM and CD21 expression in CD27⁻IgD⁻ subset of B cells. i Expression of IgG and IgM in CD27⁻IgD⁻ B cells (left) and the ratio of CD21⁻ subset among IgM-producing CD27⁻IgD⁻ B cells (right), shown as means ± SD. *p < 0.05, **p < 0.005. Error bar represents the standard deviation; NS = no significance