Table 1 |.

Therapeutic agents that target B cells

Agent	Mechanism of action	Approved indications
Anti-CD20 mAb (rituximab)*	B cell lysis	Non-Hodgkin lymphoma, chronic lymphocytic leukaemia, rheumatoid arthritis, granulomatosis with polyangiitis, and microscopic polyangiitis
Anti-CD20 mAb (obinutuzumab)	B cell lysis; greater antibody-dependent cellular cytotoxicity and direct cell death than with rituximab	Chronic lymphocytic leukaemia, follicular lymphoma
Anti-CD20 mAb (ofatumumab)	B cell lysis; binds the extracellular (large and small) loops of the CD20 molecule	Untreated or refractory chronic lymphocytic leukaemia
Anti-CD20 mAb (ocrelizumab)	B cell lysis	Multiple sclerosis
Anti-CD22 mAb (epratuzumab)	B cell lysis	No approved indications to date
Human anti-BLyS mAb (belimumab)	Blocks binding of soluble BLyS to B cell receptors, thereby inhibiting the survival of B cells and their differentiation into plasma cells	Active, autoantibody positive systemic lupus erythematous
TACI-Ig (atacicept)	blocks BLyS and APRIL thereby inhibiting B cell survival	No approved indications to date
Human anti-BLyS mAb (tabalumab)	Neutralizes the soluble form and the membrane form of BLyS	No approved indications to date

^*Rituximab is the only B cell-targeted agent that has been tested in patients with type 1 diabetes mellitus. APRIL, A proliferation-inducing ligand; BLyS, B lymphocyte stimulator (also known as BAFF); mAb, monoclonal antibody.