Fig. 4

Comparison of binding titers with FcγRIIa and FcγIIb in serum samples and the correlations with blocking rate. a Binding titers of serum samples to FcγRIIa and FcγRIIb in severe cases and non-severe cases. b Comparison of specific ratio of FcγRIIa/FcγRIIb in severe group and non-severe group. Mann–Whitney U test was used to compare differences between the two groups. Correlations between blocking percentage and FcγRIIa titer (c), FcγRIIb titer (d), FcγRIIa/ FcγRIIb (e). Red dots, r1 and P1 represent sample from severe cases; blue dots, r2 and P2 represent samples from non-severe cases. P values < 0.05 and r > 0.3 or < − 0.3 were considered statistically significant