CD19 and systemic lupus erythematosus: It is also reported that CD19+CD24hiCD38hi Breg cells are enriched in some SLE patients, together with elevated serum IL-10 level from Breg cells and reduced IL-10R in circulating lymphocytes, demonstrating that IL-10 secreted from Breg cells in human is not necessarily protective in autoimmune diseases, and can be targeted in some cases (96).