CD27 and systemic lupus erythematosus: PBMCs from individuals heterozygous for N97K or E323G variants also had decreased P2RY8 expression in switched memory (SwM) B cells and B cells double-negative (DN) for CD27 and IgD that are typically expanded in lupus (Fig. S3 H and Fig. 5 A; Jenks et al., 2018; Wang et al., 2018).