CD19 and rheumatoid arthritis: B-cell depleting treatments targeting CD19, CD20, B-cell activating factors (BAFFs), and B-cell maturation antigens (BCMAs) play a key role in the context of antibody-mediated autoimmune disorders; in particular, chimeric anti-CD20 rituximab can be employed in rheumatoid arthritis, systemic lupus erythematosus (SLE), and granulomatosis in polyangiitis, humanized anti-CD20 ocrelizumab, and ofatumumab in multiple sclerosis, veltuzumab in immune thrombocytopenia, humanized anti-CD19 inebilizumab in neuromyelitis optica spectrum disorders, and anti-BAFF belimumab in SLE.