FCGR2B and systemic lupus erythematosus: We confirmed that the expression of FcγRIIb varied between B cell subpopulations in SLE (Supplementary Figure 2A, available on the Arthritis & Rheumatology web site at http://onlinelibrary.wiley.com/doi/10.1002/art.39167/abstract), with naive cells < double‐negative cells < postswitched cells < preswitched cells.