The proportion of CD27‐IgD‐ B cells is elevated in patients with SLE, further indicating that this increase is associated with disease activity and the presence of specific antibodies such as anti‐dsDNA, anti‐Smith (Sm) and anti‐ribonucleoprotein (RNP and 9G4) antibodies.40, 43, 54. This evidence concerns the gene CD27 and systemic lupus erythematosus.