Comparative phenotypic analysis of blood CD27 IgD IgM B cell-subsets (CD27+IgD+) from controls and SLE patients. This B cell-subset was examined for the surface expression of different molecules. A. Representative histograms depict the expression of IgM, CD80, CD86, CXCR3, CXCR4 and CD95 for a healthy control and a SLE patient. For each baseline plot, negative isotypic antibody controls are superimposed in dotted lines. B. Bar histograms show the percentages of positive CD27+IgD+ B cells (upper) and the mean fluorescence intensity (lower) for each marker in healthy controls (N = 10; open bars) and SLE patients (N = 10; grey bars). C. Expression of 9G4 idiotype in healthy controls (N = 6) and SLE patients (N = 22) is shown. A representative histogram is shown. Results represent the mean ± SEM. P values were calculated using the Mann-Whitney test. P values lower than 0.05 were considered statistically different (marked with an asterisk). D. A comparison is shown of the chemotaxis of CD27 IgD IgM B cells from healthy controls and SLE patients induced by CXCL12, CXCL10 and CCL3. Migration in the absence of stimuli is represented as a dotted line. Results are expressed as a migration index and represent the mean ± SEM (N = 4). P-values were calculated using the Mann-Whitney test. P < 0.05 was considered statistically significant. Asterisks represent significant differences between healthy controls and SLE patients. Hashes indicate significant differences in chemokine-induced migration with respect to medium alone.