PTPRC and systemic lupus erythematosus: To further elucidate the most direct effect of ILC3s on B cells proliferation, maturation and antibody production in the context of lupus, B220+ B cells sorted from the spleen were co‐cultured ex vivo with or without small intestine‐derived ILC3s at a ratio of 10:1 for 3 days (Figure 5J).