Fig. 2.

Percentages of switched memory B cells in 12 healthy donors (HD), 33 patients with recurrent respiratory infections without specific antibody deficiency (SAD) (no SAD) and 20 patients with SAD (see text). Peripheral blood mononuclear cells were stained with monoclonal antibodies to CD27, immunoglobulin (Ig)M and IgD and analysis was performed on gated CD19⁺ B cells. Patients with SAD show markedly lower percentages of switched memory B cells (CD27⁺ IgD^-) compared to healthy donors and to patients without SAD. Bars represent median.