CD19 and systemic lupus erythematosus: In the context of B‐cell‐targeted strategies for SLE, treatments can generally be classified into the following approaches: anti‐CD19 therapy, which targets early and memory B cells; anti‐CD20 therapy, which depletes mature B cells; anti‐CD40/CD40L therapy, which interferes with B‐cell activation and autoantibody production; and sequential therapies, which combine different immunotherapeutic agents to increase overall treatment efficacy (Figure 4).