BCR and systemic lupus erythematosus: Strength of BCR signalling may also affect tolerance induction in transitional B cells.38 Therefore, we hypothesise that increased expression of CR1 associated with rs1876453, in individuals susceptible to lupus, may tolerise transitional or arrest mature dsDNA-specific B cells that encounter complement-coated apoptotic debris and, as a consequence, modify the initiation or course of lupus.