Fig. 4

Patients with persistent lung abnormalities have decreased activated B cells with phenotype double negative and increased activated B cells with phenotype unswitched. Peripheral mononuclear cells from patients with full recovery (FRG; black dots, n = 5) and persistent lung abnormalities (PLAG, red square, n = 5) were prepared for flow cytometry after 24 h of unstimulated culture. (a) First, the CD19 + gate was done; then, the CD38 expression on CD19 + cells was identified to obtain the frequency of activated total B-cells. (b) Into CD19 + CD38 + cells gate, IgD and CD27 expression were evaluated to identify activated B-cell subsets. The frequency of activated (c) double negative (DN), (d) naïve, (e) unswitched, and (f) switched B-cells is shown in graphics. Data are represented as median and IQR values; each symbol represents an individual patient. The Mann–Whitney U test performed statistical comparisons, * p < 0.05