CD27 and systemic lupus erythematosus: In particular, an increased frequency of CD11c+ B cells carrying a DN (CD27−IgD−) phenotype in SLE compared to pSS (p < 0.01) and HD (p < 0.0001) was observed, while lower frequencies of CD11c+ B cells with CD27+IgD+ (pSS and SLE vs. HD) and CD27+IgD− (SLE vs. pSS and HD) were identified (Supplementary Figure 1C).