Comparative analysis of blood B cell-subsets from SLE patients and healthy controls. CD19+ cells can be distributed into different B cell-subsets according to their additional expression of CD27 and IgD. A. Representative CD27-IgD dot plots from a control and a SLE patient indicating the distribution and percentages of these B cell-subsets: CD27-IgD+ (naïve), CD27+IgD- (S memory), CD27+IgD+ (CD27 IgD IgM), and CD27-IgD- (DN memory) B lymphocytes, and CD27highIgD- cells (PC). B. Scatter plots represent the percentages of these B cell-subsets in 31 controls (open circles) and 69 SLE patients (closed circles). The mean of each set of values is shown as a horizontal line. P values (Student's t test) are included. C. Scatter plots represent the percentage of each B cell-subset in controls and in SLE patients distributed according to disease activity (12 active and 57 inactive), and to the treatment (54 treated and 14 untreated). Symbols representing the control and the different SLE subgroups are displayed (bottom right panel). P values were calculated for the difference between the two pairs of SLE subgroups and between SLE subgroups and the control group. P values lower than 0.05 were considered statistically different (indicated as *).