Proliferating CD20hi/dim B cells expressing Bcl6 (CD20hi/dimBcl6hiKi67hi, dominating the Dark Zone) exhibited similar cell densities whereas their non-proliferating counterparts (CD20hi/dimBcl6hiKi67lo, mainly found in the Light Zone) were significantly decreased in SLE compared to control F/GCs (Figure 5C, lower panel). The gene discussed is BCL6; the disease is systemic lupus erythematosus.