Frequencies of classical MBCs (cMBCs, CD19+CD27+), class-switched cMBCs (CD19+CD27+IgA+/IgG+), atypical MBCs (aMBCs, CD19+CD27-IgA+/IgG+) and plasmablasts (PBs, CD19+CD27++CD38++) in the peripheral blood of HHCs (n = 113) and TB patients (n = 47) were determined by flow cytometry using the gating strategy shown in Fig 4. Here, CD27 is linked to tuberculosis.